diff --git a/packages/cli/src/ui/components/shared/text-buffer.ts b/packages/cli/src/ui/components/shared/text-buffer.ts
index 56ab575c96..a896a98624 100644
--- a/packages/cli/src/ui/components/shared/text-buffer.ts
+++ b/packages/cli/src/ui/components/shared/text-buffer.ts
@@ -2795,11 +2795,23 @@ export function textBufferReducer(
         newExpandedPaste = { ...newExpandedPaste, startLine: newStartLine };
       }
     }
+    let newSelectionAnchor = newState.selectionAnchor;
+    if (newSelectionAnchor) {
+      const newAnchorRow = newSelectionAnchor[0] - excess;
+      if (newAnchorRow < 0) {
+        newSelectionAnchor = null;
+      } else {
+        newSelectionAnchor = [newAnchorRow, newSelectionAnchor[1]];
+      }
+    }
     newState = {
       ...newState,
       lines: newLines,
       cursorRow: newCursorRow,
       expandedPaste: newExpandedPaste,
+      selectionAnchor: newSelectionAnchor,
+      undoStack: [],
+      redoStack: [],
     };
   }
 
diff --git a/packages/core/src/agents/local-invocation.ts b/packages/core/src/agents/local-invocation.ts
index 771be7b68a..310b69a6db 100644
--- a/packages/core/src/agents/local-invocation.ts
+++ b/packages/core/src/agents/local-invocation.ts
@@ -262,6 +262,13 @@ export class LocalSubagentInvocation extends BaseToolInvocation<
         }
 
         if (updated) {
+          const MAX_RECENT_ACTIVITY = 100;
+          if (recentActivity.length > MAX_RECENT_ACTIVITY) {
+            recentActivity.splice(
+              0,
+              recentActivity.length - MAX_RECENT_ACTIVITY,
+            );
+          }
           const progress: SubagentProgress = {
             isSubagentProgress: true,
             agentName: this.definition.name,