diff --git a/SourceGen/DisasmProject.cs b/SourceGen/DisasmProject.cs
index b7c39b1..c19c4e1 100644
--- a/SourceGen/DisasmProject.cs
+++ b/SourceGen/DisasmProject.cs
@@ -91,15 +91,20 @@ namespace SourceGen {
         public Dictionary<int, Symbol> UserLabels { get; private set; }
 
         /// <summary>
-        /// Local variable tables.
+        /// Local variable tables.  Uses file offset as key.
         /// </summary>
         public SortedList<int, LocalVariableTable> LvTables { get; private set; }
 
         /// <summary>
-        /// Format descriptors for operands and data items; uses file offset as key.
+        /// Format descriptors for operands and data items.  Uses file offset as key.
         /// </summary>
         public SortedList<int, FormatDescriptor> OperandFormats { get; private set; }
 
+        /// <summary>
+        /// Visualization sets.  Uses file offset as key.
+        /// </summary>
+        public SortedList<int, VisualizationSet> VisualizationSets { get; private set; }
+
         /// <summary>
         /// Project properties.  Includes CPU type, platform symbol file names, project
         /// symbols, etc.
@@ -243,6 +248,7 @@ namespace SourceGen {
             UserLabels = new Dictionary<int, Symbol>();
             OperandFormats = new SortedList<int, FormatDescriptor>();
             LvTables = new SortedList<int, LocalVariableTable>();
+            VisualizationSets = new SortedList<int, VisualizationSet>();
             ProjectProps = new ProjectProperties();
 
             SymbolTable = new SymbolTable();
@@ -2248,6 +2254,22 @@ namespace SourceGen {
                                 UndoableChange.ReanalysisScope.DataOnly);
                         }
                         break;
+                    case UndoableChange.ChangeType.SetVisualizationSet: {
+                            VisualizationSets.TryGetValue(offset, out VisualizationSet current);
+                            if (current != (VisualizationSet)oldValue) {
+                                Debug.WriteLine("GLITCH: old visSet value mismatch: current=" +
+                                    current + " old=" + (VisualizationSet)oldValue);
+                                Debug.Assert(false);
+                            }
+                            if (newValue == null) {
+                                VisualizationSets.Remove(offset);
+                            } else {
+                                VisualizationSets[offset] = (VisualizationSet)newValue;
+                            }
+                            Debug.Assert(uc.ReanalysisRequired ==
+                                UndoableChange.ReanalysisScope.DisplayOnly);
+                        }
+                        break;
                     default:
                         break;
                 }
diff --git a/SourceGen/Exporter.cs b/SourceGen/Exporter.cs
index b1adc25..0e2fa1c 100644
--- a/SourceGen/Exporter.cs
+++ b/SourceGen/Exporter.cs
@@ -314,6 +314,8 @@ namespace SourceGen {
                 case LineListGen.Line.Type.Note:
                     TextUtil.AppendPaddedString(sb, parts.Comment, mColStart[(int)Col.Label]);
                     break;
+                case LineListGen.Line.Type.VisualizationSet:
+                    break;      // TODO(xyzzy)
                 case LineListGen.Line.Type.Blank:
                     break;
                 default:
@@ -617,6 +619,8 @@ namespace SourceGen {
                     colPos = AddSpacedString(sb, colPos, mColStart[(int)Col.Label], cstr,
                         parts.Comment.Length);
                     break;
+                case LineListGen.Line.Type.VisualizationSet:
+                    break;      // TODO(xyzzy)
                 case LineListGen.Line.Type.Blank:
                     break;
                 default:
diff --git a/SourceGen/LineListGen.cs b/SourceGen/LineListGen.cs
index cbda18d..5c1e5ff 100644
--- a/SourceGen/LineListGen.cs
+++ b/SourceGen/LineListGen.cs
@@ -30,7 +30,7 @@ namespace SourceGen {
     /// </summary>
     public class LineListGen {
         /// <summary>
-        /// Color multiplier for Notes.
+        /// Color multiplier for Notes.  Used for "dark" mode.
         /// </summary>
         public float NoteColorMultiplier { get; set; } = 1.0f;
 
@@ -122,6 +122,7 @@ namespace SourceGen {
 
                 // Additional metadata.
                 LocalVariableTable      = 1 << 8,
+                VisualizationSet        = 1 << 9,
             }
 
             /// <summary>
@@ -504,6 +505,13 @@ namespace SourceGen {
                     case Line.Type.LocalVariableTable:
                         parts = GenerateLvTableLine(line.FileOffset, line.SubLineIndex);
                         break;
+                    case Line.Type.VisualizationSet:
+                        // TODO(xyzzy)
+                        mProject.VisualizationSets.TryGetValue(line.FileOffset,
+                            out VisualizationSet visSet);
+                        parts = FormattedParts.CreateLongComment("!VISUALIZATION SET! " +
+                            (visSet != null ? visSet.PlaceHolder : "???"));
+                        break;
                     case Line.Type.Blank:
                         // Nothing to do.
                         parts = FormattedParts.CreateBlankLine();
@@ -971,6 +979,9 @@ namespace SourceGen {
                     StringListToLines(formatted, offset, Line.Type.LongComment,
                         longComment.BackgroundColor, NoteColorMultiplier, lines);
                 }
+                if (mProject.VisualizationSets.TryGetValue(offset, out VisualizationSet visSet)) {
+                    lines.Add(new Line(offset, 0, Line.Type.VisualizationSet));
+                }
 
                 // Local variable tables come next.  Defer rendering.
                 if (mProject.LvTables.TryGetValue(offset, out LocalVariableTable lvt)) {
diff --git a/SourceGen/MainController.cs b/SourceGen/MainController.cs
index 3d92ccf..fcf4803 100644
--- a/SourceGen/MainController.cs
+++ b/SourceGen/MainController.cs
@@ -1491,6 +1491,11 @@ namespace SourceGen {
                         EditLocalVariableTable();
                     }
                     break;
+                case LineListGen.Line.Type.VisualizationSet:
+                    if (CanEditVisualizationSet()) {
+                        EditVisualizationSet();
+                    }
+                    break;
 
                 case LineListGen.Line.Type.Code:
                 case LineListGen.Line.Type.Data:
@@ -2058,6 +2063,25 @@ namespace SourceGen {
             }
         }
 
+        public void EditProjectProperties() {
+            string projectDir = string.Empty;
+            if (!string.IsNullOrEmpty(mProjectPathName)) {
+                projectDir = Path.GetDirectoryName(mProjectPathName);
+            }
+            EditProjectProperties dlg = new EditProjectProperties(mMainWin, mProject.ProjectProps,
+                projectDir, mOutputFormatter);
+            dlg.ShowDialog();
+            ProjectProperties newProps = dlg.NewProps;
+
+            // The dialog result doesn't matter, because the user might have hit "apply"
+            // before hitting "cancel".
+            if (newProps != null) {
+                UndoableChange uc = UndoableChange.CreateProjectPropertiesChange(
+                    mProject.ProjectProps, newProps);
+                ApplyUndoableChanges(new ChangeSet(uc));
+            }
+        }
+
         public bool CanEditProjectSymbol() {
             if (SelectionAnalysis.mNumItemsSelected != 1) {
                 return false;
@@ -2119,22 +2143,37 @@ namespace SourceGen {
             }
         }
 
-        public void EditProjectProperties() {
-            string projectDir = string.Empty;
-            if (!string.IsNullOrEmpty(mProjectPathName)) {
-                projectDir = Path.GetDirectoryName(mProjectPathName);
+        public bool CanEditVisualizationSet() {
+            if (SelectionAnalysis.mNumItemsSelected != 1) {
+                return false;
             }
-            EditProjectProperties dlg = new EditProjectProperties(mMainWin, mProject.ProjectProps,
-                projectDir, mOutputFormatter);
-            dlg.ShowDialog();
-            ProjectProperties newProps = dlg.NewProps;
+            EntityCounts counts = SelectionAnalysis.mEntityCounts;
+            // Single line, must be a visualization set.
+            LineListGen.Line.Type lineType = SelectionAnalysis.mLineType;
+            return (lineType == LineListGen.Line.Type.VisualizationSet ||
+                    lineType == LineListGen.Line.Type.Code ||
+                    lineType == LineListGen.Line.Type.Data);
+        }
 
-            // The dialog result doesn't matter, because the user might have hit "apply"
-            // before hitting "cancel".
-            if (newProps != null) {
-                UndoableChange uc = UndoableChange.CreateProjectPropertiesChange(
-                    mProject.ProjectProps, newProps);
-                ApplyUndoableChanges(new ChangeSet(uc));
+        public void EditVisualizationSet() {
+            int selIndex = mMainWin.CodeListView_GetFirstSelectedIndex();
+            int offset = CodeLineList[selIndex].FileOffset;
+            mProject.VisualizationSets.TryGetValue(offset, out VisualizationSet curVisSet);
+
+            EditVisualizationSet dlg = new EditVisualizationSet(mMainWin,
+                curVisSet);
+            if (dlg.ShowDialog() != true) {
+                return;
+            }
+            if (curVisSet != dlg.NewVisSet) {
+                // New table, edited in place, or deleted.
+                UndoableChange uc = UndoableChange.CreateVisualizationSetChange(offset,
+                    curVisSet, dlg.NewVisSet);
+                Debug.WriteLine("Change " + curVisSet + " to " + dlg.NewVisSet);
+                ChangeSet cs = new ChangeSet(uc);
+                ApplyUndoableChanges(cs);
+            } else {
+                Debug.WriteLine("No change to VisualizationSet");
             }
         }
 
@@ -3579,6 +3618,10 @@ namespace SourceGen {
                         lineTypeStr = "???";
                     }
                     break;
+                case LineListGen.Line.Type.VisualizationSet:
+                    // TODO(xyzzy)
+                    lineTypeStr = "visualization set";
+                    break;
                 default:
                     lineTypeStr = "???";
                     break;
@@ -4007,7 +4050,9 @@ namespace SourceGen {
                     continue;
                 }
 
-                // Create a new user label symbol.
+                // Create a new user label symbol.  We should not be creating a duplicate name,
+                // because user labels have priority over platform symbols when populating
+                // the symbol table.
                 Symbol newSym = new Symbol(sym.Label, sym.Value, Symbol.Source.User,
                     Symbol.Type.GlobalAddr, Symbol.LabelAnnotation.None);
                 UndoableChange uc = UndoableChange.CreateLabelChange(offset, null, newSym);
diff --git a/SourceGen/SourceGen.csproj b/SourceGen/SourceGen.csproj
index 081d03c..9c76a6d 100644
--- a/SourceGen/SourceGen.csproj
+++ b/SourceGen/SourceGen.csproj
@@ -96,6 +96,7 @@
       <DependentUpon>ShowText.xaml</DependentUpon>
     </Compile>
     <Compile Include="LocalVariableTable.cs" />
+    <Compile Include="VisualizationSet.cs" />
     <Compile Include="WpfGui\AboutBox.xaml.cs">
       <DependentUpon>AboutBox.xaml</DependentUpon>
     </Compile>
@@ -132,6 +133,9 @@
     <Compile Include="WpfGui\EditProjectProperties.xaml.cs">
       <DependentUpon>EditProjectProperties.xaml</DependentUpon>
     </Compile>
+    <Compile Include="WpfGui\EditVisualizationSet.xaml.cs">
+      <DependentUpon>EditVisualizationSet.xaml</DependentUpon>
+    </Compile>
     <Compile Include="WpfGui\Export.xaml.cs">
       <DependentUpon>Export.xaml</DependentUpon>
     </Compile>
@@ -310,6 +314,10 @@
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
     </Page>
+    <Page Include="WpfGui\EditVisualizationSet.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
     <Page Include="WpfGui\Export.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
diff --git a/SourceGen/UndoableChange.cs b/SourceGen/UndoableChange.cs
index 35f6e5d..7810a8f 100644
--- a/SourceGen/UndoableChange.cs
+++ b/SourceGen/UndoableChange.cs
@@ -105,6 +105,9 @@ namespace SourceGen {
 
             // Adds, updates, or removes a local variable table.
             SetLocalVariableTable,
+
+            // Adds, updates, or removes a visualization set.
+            SetVisualizationSet,
         }
 
         /// <summary>
@@ -478,6 +481,28 @@ namespace SourceGen {
             return uc;
         }
 
+        /// <summary>
+        /// Creates an UndoableChange for a visualization set update.
+        /// </summary>
+        /// <param name="offset">Affected offset.</param>
+        /// <param name="oldVisSet">Old visualization set.</param>
+        /// <param name="newVisSet">New visualization set.</param>
+        /// <returns>Change record.</returns>
+        public static UndoableChange CreateVisualizationSetChange(int offset,
+                VisualizationSet oldVisSet, VisualizationSet newVisSet) {
+            if (oldVisSet == newVisSet) {
+                Debug.WriteLine("No-op visualization set change");
+            }
+
+            UndoableChange uc = new UndoableChange();
+            uc.Type = ChangeType.SetVisualizationSet;
+            uc.Offset = offset;
+            uc.OldValue = oldVisSet;
+            uc.NewValue = newVisSet;
+            uc.ReanalysisRequired = ReanalysisScope.DisplayOnly;    // no change to code/data
+            return uc;
+        }
+
         public override string ToString() {
             return "[UC type=" + Type + " offset=+" +
                 (HasOffset ? Offset.ToString("x6") : "N/A") + "]";
diff --git a/SourceGen/VisualizationSet.cs b/SourceGen/VisualizationSet.cs
new file mode 100644
index 0000000..2b11730
--- /dev/null
+++ b/SourceGen/VisualizationSet.cs
@@ -0,0 +1,56 @@
+/*
+ * 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.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SourceGen {
+    public class VisualizationSet {
+        // TODO(xyzzy)
+        public string PlaceHolder { get; private set; }
+
+        public VisualizationSet(string placeHolder) {
+            PlaceHolder = placeHolder;
+        }
+
+
+        public override string ToString() {
+            return "[VS: " + PlaceHolder + "]";
+        }
+
+        public static bool operator ==(VisualizationSet a, VisualizationSet b) {
+            if (ReferenceEquals(a, b)) {
+                return true;    // same object, or both null
+            }
+            if (ReferenceEquals(a, null) || ReferenceEquals(b, null)) {
+                return false;   // one is null
+            }
+            // All fields must be equal.
+            return a.PlaceHolder == b.PlaceHolder;
+        }
+        public static bool operator !=(VisualizationSet a, VisualizationSet b) {
+            return !(a == b);
+        }
+        public override bool Equals(object obj) {
+            return obj is VisualizationSet && this == (VisualizationSet)obj;
+        }
+        public override int GetHashCode() {
+            return PlaceHolder.GetHashCode();
+        }
+    }
+}
diff --git a/SourceGen/WpfGui/EditVisualizationSet.xaml b/SourceGen/WpfGui/EditVisualizationSet.xaml
new file mode 100644
index 0000000..63e1782
--- /dev/null
+++ b/SourceGen/WpfGui/EditVisualizationSet.xaml
@@ -0,0 +1,43 @@
+<!--
+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="SourceGen.WpfGui.EditVisualizationSet"
+        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:SourceGen.WpfGui"
+        mc:Ignorable="d"
+        Title="Edit Visualization Set"
+        SizeToContent="WidthAndHeight" ResizeMode="NoResize"
+        ShowInTaskbar="False" WindowStartupLocation="CenterOwner"
+        Loaded="Window_Loaded">
+
+    <Grid Margin="8">
+        <Grid.RowDefinitions>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="Auto"/>
+        </Grid.RowDefinitions>
+
+        <TextBox Grid.Column="0" Grid.Row="0" Text="{Binding PlaceHolder, UpdateSourceTrigger=PropertyChanged}"/>
+        
+        <DockPanel Grid.Column="0" Grid.Row="1" Grid.ColumnSpan="2" Margin="0,8,0,0" LastChildFill="False">
+            <Button DockPanel.Dock="Right" Content="Cancel" Width="70" Margin="8,0,0,0" IsCancel="True"/>
+            <Button DockPanel.Dock="Right" Grid.Column="1" Content="OK" Width="70"
+                    IsDefault="True" Click="OkButton_Click"/>
+        </DockPanel>
+    </Grid>
+</Window>
diff --git a/SourceGen/WpfGui/EditVisualizationSet.xaml.cs b/SourceGen/WpfGui/EditVisualizationSet.xaml.cs
new file mode 100644
index 0000000..919c2c9
--- /dev/null
+++ b/SourceGen/WpfGui/EditVisualizationSet.xaml.cs
@@ -0,0 +1,68 @@
+/*
+ * 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.Runtime.CompilerServices;
+using System.Windows;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+
+namespace SourceGen.WpfGui {
+    /// <summary>
+    /// Visualization set editor.
+    /// </summary>
+    public partial class EditVisualizationSet : Window, INotifyPropertyChanged {
+        public VisualizationSet NewVisSet { get; private set; }
+
+        public string PlaceHolder {
+            get { return mPlaceHolder; }
+            set { mPlaceHolder = value; OnPropertyChanged(); }
+        }
+        private string mPlaceHolder;
+
+        // INotifyPropertyChanged implementation
+        public event PropertyChangedEventHandler PropertyChanged;
+        private void OnPropertyChanged([CallerMemberName] string propertyName = "") {
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        }
+
+        public EditVisualizationSet(Window owner, VisualizationSet curSet) {
+            InitializeComponent();
+            Owner = owner;
+            DataContext = this;
+
+            if (curSet != null) {
+                PlaceHolder = curSet.PlaceHolder;
+            } else {
+                PlaceHolder = "New!";
+            }
+        }
+
+        private void Window_Loaded(object sender, RoutedEventArgs e) {
+
+        }
+
+        private void OkButton_Click(object sender, RoutedEventArgs e) {
+            if (string.IsNullOrEmpty(PlaceHolder)) {
+                NewVisSet = null;
+            } else {
+                NewVisSet = new VisualizationSet(PlaceHolder);
+            }
+            DialogResult = true;
+        }
+    }
+}
diff --git a/SourceGen/WpfGui/MainWindow.xaml b/SourceGen/WpfGui/MainWindow.xaml
index 40ce52d..609033c 100644
--- a/SourceGen/WpfGui/MainWindow.xaml
+++ b/SourceGen/WpfGui/MainWindow.xaml
@@ -101,6 +101,7 @@ limitations under the License.
             </RoutedUICommand>
             <RoutedUICommand x:Key="EditProjectSymbolCmd" Text="Edit Project Symbol..."/>
             <RoutedUICommand x:Key="EditStatusFlagsCmd" Text="Override Status Flags..."/>
+            <RoutedUICommand x:Key="EditVisualizationSetCmd" Text="Create/Edit Visualization Set..."/>
             <RoutedUICommand x:Key="ExitCmd" Text="Exit"/>
             <RoutedUICommand x:Key="ExportCmd" Text="Export..."/>
             <RoutedUICommand x:Key="FindNextCmd" Text="Find Next">
@@ -225,6 +226,8 @@ limitations under the License.
                         CanExecute="CanEditProjectSymbol" Executed="EditProjectSymbolCmd_Executed"/>
         <CommandBinding Command="{StaticResource EditStatusFlagsCmd}"
                         CanExecute="CanEditStatusFlags" Executed="EditStatusFlagsCmd_Executed"/>
+        <CommandBinding Command="{StaticResource EditVisualizationSetCmd}"
+                        CanExecute="CanEditVisualizationSet" Executed="EditVisualizationSetCmd_Executed"/>
         <CommandBinding Command="{StaticResource ExitCmd}"
                         Executed="ExitCmd_Executed"/>
         <CommandBinding Command="{StaticResource ExportCmd}"
@@ -368,6 +371,7 @@ limitations under the License.
                 <MenuItem Command="{StaticResource EditProjectSymbolCmd}"/>
                 <MenuItem Command="{StaticResource CreateLocalVariableTableCmd}"/>
                 <MenuItem Command="{StaticResource EditLocalVariableTableCmd}"/>
+                <MenuItem Command="{StaticResource EditVisualizationSetCmd}"/>
                 <Separator/>
                 <MenuItem Command="{StaticResource HintAsCodeEntryPointCmd}" InputGestureText="Ctrl+H, Ctrl+C"/>
                 <MenuItem Command="{StaticResource HintAsDataStartCmd}" InputGestureText="Ctrl+H, Ctrl+D"/>
diff --git a/SourceGen/WpfGui/MainWindow.xaml.cs b/SourceGen/WpfGui/MainWindow.xaml.cs
index 8e5bb1c..8445688 100644
--- a/SourceGen/WpfGui/MainWindow.xaml.cs
+++ b/SourceGen/WpfGui/MainWindow.xaml.cs
@@ -1040,6 +1040,10 @@ namespace SourceGen.WpfGui {
             e.CanExecute = IsProjectOpen() && mMainCtrl.CanEditStatusFlags();
         }
 
+        private void CanEditVisualizationSet(object sender, CanExecuteRoutedEventArgs e) {
+            e.CanExecute = IsProjectOpen() && mMainCtrl.CanEditVisualizationSet();
+        }
+
         private void CanFormatAsWord(object sender, CanExecuteRoutedEventArgs e) {
             e.CanExecute = IsProjectOpen() && mMainCtrl.CanFormatAsWord();
         }
@@ -1187,6 +1191,10 @@ namespace SourceGen.WpfGui {
             mMainCtrl.EditStatusFlags();
         }
 
+        private void EditVisualizationSetCmd_Executed(object sender, ExecutedRoutedEventArgs e) {
+            mMainCtrl.EditVisualizationSet();
+        }
+
         private void ExitCmd_Executed(object sender, ExecutedRoutedEventArgs e) {
             Close();
         }