diff --git a/css/ui.css b/css/ui.css
index 7dabaa9f..69b4588c 100644
--- a/css/ui.css
+++ b/css/ui.css
@@ -367,6 +367,7 @@ div.markdown th {
  padding:0.2em;
 }
 #sidebar {
+  overflow:auto;
 }
 #sidebar ul {
   list-style-type:none;
diff --git a/src/baseplatform.ts b/src/baseplatform.ts
index 6a676b09..644c76cd 100644
--- a/src/baseplatform.ts
+++ b/src/baseplatform.ts
@@ -1035,7 +1035,7 @@ export function dumpStackToString(platform:Platform, mem:Uint8Array|number[], st
     // see if there's a JSR on the stack here
     // TODO: make work with roms and memory maps
     var addr = read(sp) + read(sp+1)*256;
-    var jsrofs = -3;
+    var jsrofs = jsrop==0x20 ? -2 : -3; // 6502 vs Z80
     var opcode = read(addr + jsrofs); // might be out of bounds
     if (opcode == jsrop) { // JSR
       s += "\n$" + hex(sp) + ": ";