diff --git a/SourceGenWPF/AsmGen/WpfGui/GenAndAsm.xaml b/SourceGenWPF/AsmGen/WpfGui/GenAndAsm.xaml
index a9ea5c1..7d3ed4a 100644
--- a/SourceGenWPF/AsmGen/WpfGui/GenAndAsm.xaml
+++ b/SourceGenWPF/AsmGen/WpfGui/GenAndAsm.xaml
@@ -23,7 +23,8 @@ limitations under the License.
         mc:Ignorable="d"
         Title="Generate and Assemble"
         Width="800" Height="700" MinWidth="600" MinHeight="600" ResizeMode="CanResizeWithGrip"
-        ShowInTaskbar="False" WindowStartupLocation="CenterOwner" Loaded="Window_Loaded">
+        ShowInTaskbar="False" WindowStartupLocation="CenterOwner"
+        Loaded="Window_Loaded">
     <Grid Margin="8">
         <Grid.RowDefinitions>
             <RowDefinition Height="Auto"/>
diff --git a/SourceGenWPF/DisplayList.cs b/SourceGenWPF/DisplayList.cs
index f0289fa..360c797 100644
--- a/SourceGenWPF/DisplayList.cs
+++ b/SourceGenWPF/DisplayList.cs
@@ -277,12 +277,12 @@ namespace SourceGenWPF {
                 mList.Add(null);
             }
 
+            SelectedIndices = new DisplayListSelection(size);
+
             // send one big notification at the end; "reset" means "forget everything you knew"
             OnPropertyChanged(CountString);
             OnPropertyChanged(IndexerName);
             OnCollectionReset();
-
-            SelectedIndices = new DisplayListSelection(size);
         }
 
         /// <summary>
@@ -294,7 +294,7 @@ namespace SourceGenWPF {
         /// <param name="newCount">Number of new lines.  May be zero.</param>
         public void ClearListSegment(int startIndex, int oldCount, int newCount) {
             Debug.WriteLine("ClearListSegment start=" + startIndex + " old=" + oldCount +
-                " new=" + newCount);
+                " new=" + newCount + " (mList.Count=" + mList.Count + ")");
 
             Debug.Assert(startIndex >= 0 && startIndex < mList.Count);
             Debug.Assert(oldCount > 0 && startIndex + oldCount < mList.Count);
@@ -307,6 +307,11 @@ namespace SourceGenWPF {
                 mList.Insert(startIndex, null);
             }
             // TODO: can we null out existing entries, and just insert/remove when counts differ?
+
+            if (oldCount != newCount) {
+                SelectedIndices = new DisplayListSelection(mList.Count);
+            }
+
             OnPropertyChanged(CountString);
             OnPropertyChanged(IndexerName);
             OnCollectionReset();
diff --git a/SourceGenWPF/LineListGen.cs b/SourceGenWPF/LineListGen.cs
index ee5665b..aaaae5a 100644
--- a/SourceGenWPF/LineListGen.cs
+++ b/SourceGenWPF/LineListGen.cs
@@ -576,7 +576,9 @@ namespace SourceGenWPF {
         /// </summary>
         public void GenerateAll() {
             mLineList.Clear();
-            GenerateHeaderLines(mProject, mFormatter, mPseudoOpNames, mLineList);
+            List<Line> headerLines = GenerateHeaderLines(mProject, mFormatter, mPseudoOpNames);
+            mLineList.InsertRange(0, headerLines);
+
             GenerateLineList(mProject, mFormatter, mPseudoOpNames,
                 0, mProject.FileData.Length - 1, mLineList);
 
@@ -594,10 +596,22 @@ namespace SourceGenWPF {
         /// <param name="endOffset">End offset (inclusive).</param>
         public void GenerateRange(int startOffset, int endOffset) {
             if (startOffset < 0) {
-                ClearHeaderLines();
-                GenerateHeaderLines(mProject, mFormatter, mPseudoOpNames, mLineList);
+                // Clear existing header lines. Find the first non-header item.
+                int headerEndIndex = FindLineByOffset(mLineList, 0);
+                if (headerEndIndex == 0) {
+                    // no header lines present
+                    Debug.WriteLine("No header lines found");
+                } else {
+                    Debug.WriteLine("Removing " + headerEndIndex + " header lines");
+                    mLineList.RemoveRange(0, headerEndIndex);
+                }
+
+                List<Line> headerLines = GenerateHeaderLines(mProject, mFormatter, mPseudoOpNames);
+                mLineList.InsertRange(0, headerLines);
+                mDisplayList.ClearListSegment(0, headerEndIndex, headerLines.Count);
+
                 if (endOffset < 0) {
-                    // nothing else to do
+                    // nothing else to do -- header-only change
                     return;
                 }
                 // do the rest
@@ -708,21 +722,20 @@ namespace SourceGenWPF {
             return true;
         }
 
-        /// <summary>
-        /// Removes all header lines from the display list.
-        /// </summary>
-        private void ClearHeaderLines() {
-            // Find the first non-header item.
-            int endIndex = FindLineByOffset(mLineList, 0);
-            if (endIndex == 0) {
-                // no header lines present
-                Debug.WriteLine("No header lines found");
-                return;
-            }
-            Debug.WriteLine("Removing " + endIndex + " header lines");
-            mLineList.RemoveRange(0, endIndex);
-            mDisplayList.ClearListSegment(0, endIndex, 0);
-        }
+        ///// <summary>
+        ///// Removes all header lines from the line list.
+        ///// </summary>
+        //private void ClearHeaderLines() {
+        //    // Find the first non-header item.
+        //    int endIndex = FindLineByOffset(mLineList, 0);
+        //    if (endIndex == 0) {
+        //        // no header lines present
+        //        Debug.WriteLine("No header lines found");
+        //        return;
+        //    }
+        //    Debug.WriteLine("Removing " + endIndex + " header lines");
+        //    mLineList.RemoveRange(0, endIndex);
+        //}
 
         /// <summary>
         /// Generates a synthetic offset for the FileOffset field from an index value.  The
@@ -745,18 +758,14 @@ namespace SourceGenWPF {
         }
 
         /// <summary>
-        /// Generates the header lines (header comment, EQU directives), and inserts them at
-        /// the top of the list.
-        /// 
-        /// This does not currently do incremental generation.  Call ClearHeaderLines() before
-        /// calling here if you're not starting with an empty list.
+        /// Generates the header lines (header comment, EQU directives).
         /// </summary>
         /// <param name="proj">Project reference.</param>
         /// <param name="formatter">Output formatter.</param>
         /// <param name="opNames">Pseudo-op names.</param>
-        /// <param name="fullLines">List to add output lines to.</param>
-        private static void GenerateHeaderLines(DisasmProject proj, Formatter formatter,
-                PseudoOp.PseudoOpNames opNames, List<Line> fullLines) {
+        /// <returns>List with header lines.</returns>
+        private static List<Line> GenerateHeaderLines(DisasmProject proj, Formatter formatter,
+                PseudoOp.PseudoOpNames opNames) {
             List<Line> tmpLines = new List<Line>();
             Line line;
             FormattedParts parts;
@@ -793,7 +802,7 @@ namespace SourceGenWPF {
                 tmpLines.Add(line);
             }
 
-            fullLines.InsertRange(0, tmpLines);
+            return tmpLines;
         }
 
         /// <summary>
diff --git a/SourceGenWPF/MainController.cs b/SourceGenWPF/MainController.cs
index d59accd..61e354e 100644
--- a/SourceGenWPF/MainController.cs
+++ b/SourceGenWPF/MainController.cs
@@ -212,6 +212,9 @@ namespace SourceGenWPF {
             mMainWin.UpdateRecentLinks();
 
             ProcessCommandLine();
+
+            // Create an initial value.
+            SelectionAnalysis = UpdateSelectionState();
         }
 
         private void ProcessCommandLine() {
@@ -1210,11 +1213,9 @@ namespace SourceGenWPF {
                     }
                     break;
                 case LineListGen.Line.Type.LongComment:
-#if false
-                    if (editLongCommentToolStripMenuItem.Enabled) {
-                        EditLongComment_Click(sender, e);
+                    if (CanEditLongComment()) {
+                        EditLongComment();
                     }
-#endif
                     break;
                 case LineListGen.Line.Type.Note:
 #if false
@@ -1355,6 +1356,10 @@ namespace SourceGenWPF {
             }
         }
 
+        public void EditHeaderComment() {
+            EditLongComment(LineListGen.Line.HEADER_COMMENT_OFFSET);
+        }
+
         public bool CanEditLabel() {
             if (SelectionAnalysis.mNumItemsSelected != 1) {
                 return false;
@@ -1395,12 +1400,48 @@ namespace SourceGenWPF {
             }
         }
 
+        public bool CanEditLongComment() {
+            if (SelectionAnalysis.mNumItemsSelected != 1) {
+                return false;
+            }
+            EntityCounts counts = SelectionAnalysis.mEntityCounts;
+            // Single line, code or data, or a long comment.
+            return (counts.mDataLines > 0 || counts.mCodeLines > 0 ||
+                SelectionAnalysis.mLineType == LineListGen.Line.Type.LongComment);
+        }
+
+        public void EditLongComment() {
+            int selIndex = mMainWin.CodeListView_GetFirstSelectedIndex();
+            int offset = CodeLineList[selIndex].FileOffset;
+            EditLongComment(offset);
+        }
+
+        private void EditLongComment(int offset) {
+            EditLongComment dlg = new EditLongComment(mMainWin, mOutputFormatter);
+            if (mProject.LongComments.TryGetValue(offset, out MultiLineComment oldComment)) {
+                dlg.LongComment = oldComment;
+            }
+            dlg.ShowDialog();
+
+            if (dlg.DialogResult == true) {
+                MultiLineComment newComment = dlg.LongComment;
+                if (oldComment != newComment) {
+                    Debug.WriteLine("Changing long comment at +" + offset.ToString("x6"));
+
+                    UndoableChange uc = UndoableChange.CreateLongCommentChange(offset,
+                        oldComment, newComment);
+                    ChangeSet cs = new ChangeSet(uc);
+                    ApplyUndoableChanges(cs);
+                }
+            }
+        }
+
         public bool CanEditStatusFlags() {
             if (SelectionAnalysis.mNumItemsSelected != 1) {
                 return false;
             }
             EntityCounts counts = SelectionAnalysis.mEntityCounts;
-            // Line must be code, or a RegWidth directive.
+            // Single line, must be code or a RegWidth directive.
             return (SelectionAnalysis.mLineType == LineListGen.Line.Type.Code ||
                 SelectionAnalysis.mLineType == LineListGen.Line.Type.RegWidthDirective);
         }
diff --git a/SourceGenWPF/SourceGenWPF.csproj b/SourceGenWPF/SourceGenWPF.csproj
index d85b673..840416d 100644
--- a/SourceGenWPF/SourceGenWPF.csproj
+++ b/SourceGenWPF/SourceGenWPF.csproj
@@ -90,6 +90,9 @@
     <Compile Include="WpfGui\EditLabel.xaml.cs">
       <DependentUpon>EditLabel.xaml</DependentUpon>
     </Compile>
+    <Compile Include="WpfGui\EditLongComment.xaml.cs">
+      <DependentUpon>EditLongComment.xaml</DependentUpon>
+    </Compile>
     <Compile Include="WpfGui\EditProjectProperties.xaml.cs">
       <DependentUpon>EditProjectProperties.xaml</DependentUpon>
     </Compile>
@@ -213,6 +216,10 @@
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
     </Page>
+    <Page Include="WpfGui\EditLongComment.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
     <Page Include="WpfGui\EditProjectProperties.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
diff --git a/SourceGenWPF/WpfGui/EditLongComment.xaml b/SourceGenWPF/WpfGui/EditLongComment.xaml
new file mode 100644
index 0000000..da07ba4
--- /dev/null
+++ b/SourceGenWPF/WpfGui/EditLongComment.xaml
@@ -0,0 +1,78 @@
+<!--
+Copyright 2019 faddenSoft
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+
+<Window x:Class="SourceGenWPF.WpfGui.EditLongComment"
+        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        xmlns:local="clr-namespace:SourceGenWPF.WpfGui"
+        mc:Ignorable="d"
+        Title="Edit Long Comment"
+        Width="584" Height="700" MinWidth="584" MinHeight="600" ResizeMode="CanResizeWithGrip"
+        ShowInTaskbar="False" WindowStartupLocation="CenterOwner"
+        Loaded="Window_Loaded"
+        Closing="Window_Closing">
+
+    <Window.Resources>
+        <RoutedUICommand x:Key="CloseCmd">
+            <RoutedUICommand.InputGestures>
+                <KeyGesture>Ctrl+Enter</KeyGesture>
+            </RoutedUICommand.InputGestures>
+        </RoutedUICommand>
+    </Window.Resources>
+    <Window.CommandBindings>
+        <CommandBinding Command="{StaticResource CloseCmd}" Executed="CloseCmd_Executed"/>
+    </Window.CommandBindings>
+
+    <Grid Margin="8">
+        <Grid.RowDefinitions>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="*"/>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="*"/>
+            <RowDefinition Height="Auto"/>
+        </Grid.RowDefinitions>
+
+        <TextBlock Grid.Row="0" Text="Enter comment text:"/>
+
+        <TextBox Name="entryTextBox" Grid.Row="1"
+                 Text="{Binding UserInput, UpdateSourceTrigger=PropertyChanged,
+                    FallbackValue=01234567890123456789012345678901234567890123456789012345678901234567890123456789}"
+                 FontFamily="{StaticResource GeneralMonoFont}" VerticalScrollBarVisibility="Visible"
+                 AcceptsReturn="True" TextWrapping="Wrap"/>
+
+        <StackPanel Grid.Row="2" Orientation="Horizontal" Margin="0,20,0,0">
+            <TextBlock Text="Maximum line width:"/>
+            <ComboBox Name="maxWidthComboBox" Width="75" Margin="8,0,0,0"
+                      ItemsSource="{Binding LineWidthItems}" SelectionChanged="MaxWidthComboBox_SelectionChanged"/>
+            <CheckBox Content="Render in box" Margin="40,1,0,0" IsChecked="{Binding RenderInBox}"/>
+        </StackPanel>
+
+        <TextBlock Grid.Row="3" Text="Expected output:" Margin="0,20,0,0"/>
+        <TextBox Name="displayTextBox" Grid.Row="4"
+                 Text="{Binding TextOutput,
+                    FallbackValue=01234567890123456789012345678901234567890123456789012345678901234567890123456789}"
+                 FontFamily="{StaticResource GeneralMonoFont}" VerticalScrollBarVisibility="Visible"
+                 IsReadOnly="True"/>
+
+        <StackPanel Grid.Row="5" Orientation="Horizontal" HorizontalAlignment="Right" Margin="0,8,0,0">
+            <Button Content="OK" IsDefault="True" Width="70" Click="OkButton_Clicked"/>
+            <Button Content="Cancel" IsCancel="True" Width="70" Margin="4,0,0,0"/>
+        </StackPanel>
+    </Grid>
+</Window>
diff --git a/SourceGenWPF/WpfGui/EditLongComment.xaml.cs b/SourceGenWPF/WpfGui/EditLongComment.xaml.cs
new file mode 100644
index 0000000..c27eb8b
--- /dev/null
+++ b/SourceGenWPF/WpfGui/EditLongComment.xaml.cs
@@ -0,0 +1,177 @@
+/*
+ * Copyright 2019 faddenSoft
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+using System.Text;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Input;
+
+namespace SourceGenWPF.WpfGui {
+    /// <summary>
+    /// Long comment editor.
+    /// </summary>
+    public partial class EditLongComment : Window, INotifyPropertyChanged {
+        /// <summary>
+        /// Get or set the multi-line comment object.  On exit, will be set to null if
+        /// the user wants to delete the comment.
+        /// </summary>
+        public MultiLineComment LongComment { get; set; }
+
+        private Asm65.Formatter mFormatter;
+
+        public bool RenderInBox {
+            get { return mRenderInBox; }
+            set {
+                mRenderInBox = value;
+                OnPropertyChanged();
+                FormatInput();
+            }
+        }
+        private bool mRenderInBox;
+
+        /// <summary>
+        /// Text input by user.  This is bound to the input TextBox.
+        /// </summary>
+        public string UserInput {
+            get { return mUserInput; }
+            set {
+                mUserInput = value;
+                OnPropertyChanged();
+                FormatInput();
+            }
+        }
+        private string mUserInput;
+
+        /// <summary>
+        /// Generated text output.  This is bound to the output TextBox.
+        /// </summary>
+        public string TextOutput {
+            get { return mTextOutput; }
+            set {
+                mTextOutput = value;
+                OnPropertyChanged();
+            }
+        }
+        private string mTextOutput;
+
+        // INotifyPropertyChanged implementation
+        public event PropertyChangedEventHandler PropertyChanged;
+        private void OnPropertyChanged([CallerMemberName] string propertyName = "") {
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        }
+
+        /// <summary>
+        /// ItemsSource for line width combo box.
+        /// </summary>
+        public int[] LineWidthItems { get; } = new int[] { 30, 40, 64, 80 };
+
+
+        public EditLongComment(Window owner, Asm65.Formatter formatter) {
+            InitializeComponent();
+            Owner = owner;
+            DataContext = this;
+
+            mFormatter = formatter;
+            LongComment = new MultiLineComment(string.Empty);
+        }
+
+        private void Window_Loaded(object sender, RoutedEventArgs e) {
+            Debug.Assert(LongComment != null);
+            UserInput = LongComment.Text;
+            RenderInBox = LongComment.BoxMode;
+
+            // Try to find a match for the max width specified in the MLC.
+            maxWidthComboBox.SelectedIndex = 0;
+            for (int i = 0; i < maxWidthComboBox.Items.Count; i++) {
+                if ((int)maxWidthComboBox.Items[i] == LongComment.MaxWidth) {
+                    maxWidthComboBox.SelectedIndex = i;
+                    break;
+                }
+            }
+
+            FormatInput();
+            entryTextBox.Focus();
+        }
+
+        private void OkButton_Clicked(object sender, RoutedEventArgs e) {
+            DialogResult = true;
+        }
+
+        // Handle Ctrl+Enter as a way to close the dialog, since plain Enter just
+        // moves to a new line.
+        private void CloseCmd_Executed(object sender, ExecutedRoutedEventArgs e) {
+            DialogResult = true;
+        }
+
+        private void Window_Closing(object sender, CancelEventArgs e) {
+            if (string.IsNullOrEmpty(UserInput)) {
+                LongComment = null;
+            } else {
+                LongComment = CreateMLC();
+            }
+        }
+
+        private void MaxWidthComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e) {
+            FormatInput();
+        }
+
+        /// <summary>
+        /// Formats entryTextBox.Text into displayTextBox.Text.
+        /// </summary>
+        private void FormatInput() {
+            if (!IsLoaded) {
+                return;
+            }
+
+            MultiLineComment mlc = CreateMLC();
+            if (mlc == null) {
+                return;
+            }
+            List<string> lines = mlc.FormatText(mFormatter, string.Empty);
+
+            StringBuilder sb = new StringBuilder(UserInput.Length + lines.Count * 2);
+            //sb.AppendFormat("### got {0} lines\r\n", lines.Count);
+            bool first = true;
+            foreach (string line in lines) {
+                if (first) {
+                    first = false;
+                } else {
+                    sb.Append("\r\n");
+                }
+                sb.Append(line);
+            }
+
+            TextOutput = sb.ToString();
+        }
+
+        /// <summary>
+        /// Creates a MultiLineComment from the current state of the dialog.
+        /// </summary>
+        /// <returns>New MultiLineComment object.  Returns null if the dialog is still
+        ///   in the process of initializing.</returns>
+        private MultiLineComment CreateMLC() {
+            if (maxWidthComboBox.SelectedItem == null) {
+                return null;    // still initializing
+            }
+            return new MultiLineComment(UserInput, RenderInBox,
+                (int)maxWidthComboBox.SelectedItem);
+        }
+    }
+}
diff --git a/SourceGenWPF/WpfGui/MainWindow.xaml b/SourceGenWPF/WpfGui/MainWindow.xaml
index 6bf1eac..eb012ea 100644
--- a/SourceGenWPF/WpfGui/MainWindow.xaml
+++ b/SourceGenWPF/WpfGui/MainWindow.xaml
@@ -57,11 +57,17 @@ limitations under the License.
             <RoutedUICommand x:Key="DebugSourceGenerationTestsCmd" Text="Source Generation Tests..."/>
             <RoutedUICommand x:Key="EditAddressCmd" Text="Set Address..."/>
             <RoutedUICommand x:Key="EditAppSettingsCmd" Text="Settings..."/>
+            <RoutedUICommand x:Key="EditHeaderCommentCmd" Text="Edit Header Comment..."/>
             <RoutedUICommand x:Key="EditLabelCmd" Text="Edit Label...">
                 <RoutedUICommand.InputGestures>
                     <KeyGesture>Ctrl+L</KeyGesture>
                 </RoutedUICommand.InputGestures>
             </RoutedUICommand>
+            <RoutedUICommand x:Key="EditLongCommentCmd" Text="Edit Long Comment...">
+                <RoutedUICommand.InputGestures>
+                    <KeyGesture>Ctrl+M</KeyGesture>
+                </RoutedUICommand.InputGestures>
+            </RoutedUICommand>
             <RoutedUICommand x:Key="EditStatusFlagsCmd" Text="Override Status Flags..."/>
             <RoutedUICommand x:Key="ExitCmd" Text="Exit"/>
             <RoutedUICommand x:Key="FindNextCmd" Text="Find Next">
@@ -128,8 +134,12 @@ limitations under the License.
                         Executed="DebugSourceGenerationTestsCmd_Executed"/>
         <CommandBinding Command="{StaticResource EditAddressCmd}"
                         CanExecute="CanEditAddress" Executed="EditAddressCmd_Executed"/>
+        <CommandBinding Command="{StaticResource EditHeaderCommentCmd}"
+                        CanExecute="IsProjectOpen" Executed="EditHeaderCommentCmd_Executed"/>
         <CommandBinding Command="{StaticResource EditLabelCmd}"
                         CanExecute="CanEditLabel" Executed="EditLabelCmd_Executed"/>
+        <CommandBinding Command="{StaticResource EditLongCommentCmd}"
+                        CanExecute="CanEditLongComment" Executed="EditLongCommentCmd_Executed"/>
         <CommandBinding Command="{StaticResource EditStatusFlagsCmd}"
                         CanExecute="CanEditStatusFlags" Executed="EditStatusFlagsCmd_Executed"/>
         <CommandBinding Command="{StaticResource ExitCmd}"
@@ -204,7 +214,7 @@ limitations under the License.
                 <MenuItem Command="{StaticResource FindNextCmd}"/>
                 <MenuItem Command="{StaticResource GotoCmd}"/>
                 <Separator/>
-                <MenuItem Header="Edit Header Comment..."/>
+                <MenuItem Command="{StaticResource EditHeaderCommentCmd}"/>
                 <MenuItem Command="Properties" Header="Project Properties..."/>
                 <MenuItem Header="Toggle Data Scan"/> <!-- Ctrl+D -->
                 <Separator/>
@@ -216,7 +226,7 @@ limitations under the License.
                 <MenuItem Command="{StaticResource EditLabelCmd}"/>
                 <MenuItem Header="Edit Operand..."/> <!-- Ctrl+O -->
                 <MenuItem Header="Edit Comment..."/> <!-- Ctrl+; -->
-                <MenuItem Header="Edit Long Comment..."/> <!-- Ctrl+M -->
+                <MenuItem Command="{StaticResource EditLongCommentCmd}"/>
                 <MenuItem Header="Edit Note..."/>    <!-- Ctrl+N -->
                 <MenuItem Header="Edit Project Symbol..."/>
                 <Separator/>
@@ -428,23 +438,23 @@ limitations under the License.
                 </ListView.Resources>
                 <ListView.View>
                     <GridView AllowsColumnReorder="False">
-                        <GridViewColumn Header="Offset" Width="58"
+                        <GridViewColumn Header="Offset" Width="60"
                                         DisplayMemberBinding="{Binding Offset}"/>
-                        <GridViewColumn Header="Addr" Width="58"
+                        <GridViewColumn Header="Addr" Width="60"
                                         CellTemplate="{StaticResource addrHighlightTemplate}"/>
-                        <GridViewColumn Header="Bytes" Width="85"
+                        <GridViewColumn Header="Bytes" Width="93"
                                         DisplayMemberBinding="{Binding Bytes}"/>
-                        <GridViewColumn Header="Flags" Width="78"
+                        <GridViewColumn Header="Flags" Width="80"
                                         DisplayMemberBinding="{Binding Flags}"/>
-                        <GridViewColumn Header="Attr" Width="52"
+                        <GridViewColumn Header="Attr" Width="54"
                                         DisplayMemberBinding="{Binding Attr}"/>
-                        <GridViewColumn Header="Label" Width="71"
+                        <GridViewColumn Header="Label" Width="73"
                                         CellTemplate="{StaticResource labelHighlightTemplate}"/>
-                        <GridViewColumn Header="Opcode" Width="58"
+                        <GridViewColumn Header="Opcode" Width="60"
                                         DisplayMemberBinding="{Binding Opcode}"/>
-                        <GridViewColumn Header="Operand" Width="98"
+                        <GridViewColumn Header="Operand" Width="100"
                                         DisplayMemberBinding="{Binding Operand}"/>
-                        <GridViewColumn Header="Comment" Width="342"
+                        <GridViewColumn Header="Comment" Width="344"
                                         DisplayMemberBinding="{Binding Comment}"/>
                     </GridView>
                 </ListView.View>
diff --git a/SourceGenWPF/WpfGui/MainWindow.xaml.cs b/SourceGenWPF/WpfGui/MainWindow.xaml.cs
index dd65532..9b0a688 100644
--- a/SourceGenWPF/WpfGui/MainWindow.xaml.cs
+++ b/SourceGenWPF/WpfGui/MainWindow.xaml.cs
@@ -730,39 +730,39 @@ namespace SourceGenWPF.WpfGui {
 
         #region Can-execute handlers
 
+        /// <summary>
+        /// Returns true if the project is open.
+        /// </summary>
+        /// <returns></returns>
+        private bool IsProjectOpen() {
+            return mMainCtrl != null && mMainCtrl.IsProjectOpen();
+        }
+
         /// <summary>
         /// Returns true if the project is open.  Intended for use in XAML CommandBindings.
         /// </summary>
         private void IsProjectOpen(object sender, CanExecuteRoutedEventArgs e) {
-            e.CanExecute = mMainCtrl != null && mMainCtrl.IsProjectOpen();
+            e.CanExecute = IsProjectOpen();
         }
 
         private void CanEditAddress(object sender, CanExecuteRoutedEventArgs e) {
-            if (mMainCtrl == null || !mMainCtrl.IsProjectOpen()) {
-                e.CanExecute = false;
-                return;
-            }
-            e.CanExecute = mMainCtrl.CanEditAddress();
+            e.CanExecute = IsProjectOpen() && mMainCtrl.CanEditAddress();
         }
 
         private void CanEditLabel(object sender, CanExecuteRoutedEventArgs e) {
-            if (mMainCtrl == null || !mMainCtrl.IsProjectOpen()) {
-                e.CanExecute = false;
-                return;
-            }
-            e.CanExecute = mMainCtrl.CanEditLabel();
+            e.CanExecute = IsProjectOpen() && mMainCtrl.CanEditLabel();
+        }
+
+        private void CanEditLongComment(object sender, CanExecuteRoutedEventArgs e) {
+            e.CanExecute = IsProjectOpen() && mMainCtrl.CanEditLongComment();
         }
 
         private void CanEditStatusFlags(object sender, CanExecuteRoutedEventArgs e) {
-            if (mMainCtrl == null || !mMainCtrl.IsProjectOpen()) {
-                e.CanExecute = false;
-                return;
-            }
-            e.CanExecute = mMainCtrl.CanEditStatusFlags();
+            e.CanExecute = IsProjectOpen() && mMainCtrl.CanEditStatusFlags();
         }
 
         private void CanHintAsCodeEntryPoint(object sender, CanExecuteRoutedEventArgs e) {
-            if (mMainCtrl == null || !mMainCtrl.IsProjectOpen()) {
+            if (!IsProjectOpen()) {
                 e.CanExecute = false;
                 return;
             }
@@ -771,7 +771,7 @@ namespace SourceGenWPF.WpfGui {
                 (counts.mDataHints != 0 || counts.mInlineDataHints != 0 || counts.mNoHints != 0);
         }
         private void CanHintAsDataStart(object sender, CanExecuteRoutedEventArgs e) {
-            if (mMainCtrl == null || !mMainCtrl.IsProjectOpen()) {
+            if (!IsProjectOpen()) {
                 e.CanExecute = false;
                 return;
             }
@@ -780,7 +780,7 @@ namespace SourceGenWPF.WpfGui {
                 (counts.mCodeHints != 0 || counts.mInlineDataHints != 0 || counts.mNoHints != 0);
         }
         private void CanHintAsInlineData(object sender, CanExecuteRoutedEventArgs e) {
-            if (mMainCtrl == null || !mMainCtrl.IsProjectOpen()) {
+            if (!IsProjectOpen()) {
                 e.CanExecute = false;
                 return;
             }
@@ -789,7 +789,7 @@ namespace SourceGenWPF.WpfGui {
                 (counts.mCodeHints != 0 || counts.mDataHints != 0 || counts.mNoHints != 0);
         }
         private void CanRemoveHints(object sender, CanExecuteRoutedEventArgs e) {
-            if (mMainCtrl == null || !mMainCtrl.IsProjectOpen()) {
+            if (!IsProjectOpen()) {
                 e.CanExecute = false;
                 return;
             }
@@ -799,17 +799,17 @@ namespace SourceGenWPF.WpfGui {
         }
 
         private void CanNavigateBackward(object sender, CanExecuteRoutedEventArgs e) {
-            e.CanExecute = mMainCtrl != null && mMainCtrl.CanNavigateBackward();
+            e.CanExecute = IsProjectOpen() && mMainCtrl.CanNavigateBackward();
         }
         private void CanNavigateForward(object sender, CanExecuteRoutedEventArgs e) {
-            e.CanExecute = mMainCtrl != null && mMainCtrl.CanNavigateForward();
+            e.CanExecute = IsProjectOpen() && mMainCtrl.CanNavigateForward();
         }
 
         private void CanRedo(object sender, CanExecuteRoutedEventArgs e) {
-            e.CanExecute = mMainCtrl != null && mMainCtrl.CanRedo();
+            e.CanExecute = IsProjectOpen() && mMainCtrl.CanRedo();
         }
         private void CanUndo(object sender, CanExecuteRoutedEventArgs e) {
-            e.CanExecute = mMainCtrl != null && mMainCtrl.CanUndo();
+            e.CanExecute = IsProjectOpen() && mMainCtrl.CanUndo();
         }
 
         #endregion Can-execute handlers
@@ -844,10 +844,18 @@ namespace SourceGenWPF.WpfGui {
             mMainCtrl.EditAppSettings();
         }
 
+        private void EditHeaderCommentCmd_Executed(object sender, ExecutedRoutedEventArgs e) {
+            mMainCtrl.EditHeaderComment();
+        }
+
         private void EditLabelCmd_Executed(object sender, ExecutedRoutedEventArgs e) {
             mMainCtrl.EditLabel();
         }
 
+        private void EditLongCommentCmd_Executed(object sender, ExecutedRoutedEventArgs e) {
+            mMainCtrl.EditLongComment();
+        }
+
         private void EditStatusFlagsCmd_Executed(object sender, ExecutedRoutedEventArgs e) {
             mMainCtrl.EditStatusFlags();
         }