fix: refresh scroller layout when tool confirmation dialog is cancelled

When the user cancels a subagent tool confirmation dialog, the subagent
panel stays expanded at its pre-cancel height. This happens because
cancelConfirmation() only called parent.layout() (relaying the turn
widget's children), but never updated the ScrolledComposite's minimum
size via refreshScrollerLayout(). On the Continue path this goes
unnoticed because subsequent subagent messages trigger a layout refresh;
on the Cancel path no further messages arrive, so the panel is stuck.

Fix by adding a dispose listener on the dialog in BaseTurnWidget that
walks up to the nearest ChatContentViewer and calls
requestRefreshScrollerLayout(), a new coalesced async helper that
schedules a single refreshScrollerLayout() after pending SWT mutations
settle. InvokeToolConfirmationDialog remains self-contained: both the
accept and cancel paths use a private disposeAndRequestParentLayout()
helper, keeping scroller-specific behaviour out of the dialog.

Fixes #169

Author: rsd-darshan

com.microsoft.copilot.eclipse.ui/src/com/microsoft/copilot/eclipse/ui/chat/BaseTurnWidget.java

@@ -649,17 +649,17 @@ public CompletableFuture<LanguageModelToolConfirmationResult> requestToolExecuti
       ConfirmationContent content, Object input) {
     reset();
 
-    Runnable refreshLayout = null;
-    Composite ancestor = this.getParent();
-    while (ancestor != null && !ancestor.isDisposed()) {
-      if (ancestor instanceof ChatContentViewer) {
-        final ChatContentViewer viewer = (ChatContentViewer) ancestor;
-        refreshLayout = viewer::refreshScrollerLayout;
-        break;
+    this.confirmDialog = new InvokeToolConfirmationDialog(this, content, input);
+    this.confirmDialog.addDisposeListener(e -> {
+      Composite ancestor = this.getParent();
+      while (ancestor != null && !ancestor.isDisposed()) {
+        if (ancestor instanceof ChatContentViewer) {
+          ((ChatContentViewer) ancestor).requestRefreshScrollerLayout();
+          break;
+        }
+        ancestor = ancestor.getParent();
       }
-      ancestor = ancestor.getParent();
-    }
-    this.confirmDialog = new InvokeToolConfirmationDialog(this, content, input, refreshLayout);
+    });
     CompletableFuture<LanguageModelToolConfirmationResult> toolConfirmationFuture = this.confirmDialog
         .getConfirmationFuture();
 

com.microsoft.copilot.eclipse.ui/src/com/microsoft/copilot/eclipse/ui/chat/ChatContentViewer.java

@@ -404,6 +404,14 @@ public void renderErrorMessage(String errorMessage) {
     scrollToLatestUserTurn();
   }
 
+  /**
+   * Schedules a single async {@link #refreshScrollerLayout()} call so that multiple dispose/layout
+   * events that arrive in the same event-loop tick are coalesced into one pass.
+   */
+  public void requestRefreshScrollerLayout() {
+    SwtUtils.invokeOnDisplayThreadAsync(() -> refreshScrollerLayout(), this);
+  }
+
   /**
    * Update the size of scrolled composite when there are content updates.
    */

com.microsoft.copilot.eclipse.ui/src/com/microsoft/copilot/eclipse/ui/chat/InvokeToolConfirmationDialog.java

@@ -68,22 +68,19 @@ public class InvokeToolConfirmationDialog extends Composite {
   private Runnable titleFontChangeCallback;
   private ConfirmationContent confirmationContent;
   private ConfirmationAction selectedAction;
-  private final Runnable onCancelCallback;
 
   /**
    * Create a new confirmation dialog driven by {@link ConfirmationContent}.
    *
    * @param parent the parent composite
    * @param content confirmation content with title, message, and action buttons
    * @param input the input object to pass to the tool
-   * @param onCancelCallback invoked after the dialog is disposed on cancellation, for layout refresh
    */
   public InvokeToolConfirmationDialog(Composite parent,
-      ConfirmationContent content, Object input, Runnable onCancelCallback) {
+      ConfirmationContent content, Object input) {
     super(parent, SWT.BORDER | SWT.WRAP);
     this.setLayout(new GridLayout(1, false));
     this.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
-    this.onCancelCallback = onCancelCallback;
 
     this.confirmationContent = content;
     createDialogContent(content.getTitle(), content.getMessage(), input);
@@ -122,10 +119,7 @@ public void cancelConfirmation() {
             && StringUtils.isNotEmpty(this.cancelMessage)) {
           new AgentToolCancelLabel(parent, SWT.NONE, this.cancelMessage);
         }
-        this.dispose();
-        if (onCancelCallback != null) {
-          onCancelCallback.run();
-        }
+        disposeAndRequestParentLayout();
       }, this);
     }
   }
@@ -321,6 +315,10 @@ private void acceptAndDispose(ConfirmationAction action) {
         new LanguageModelToolConfirmationResult(
             ToolConfirmationResult.ACCEPT));
 
+    disposeAndRequestParentLayout();
+  }
+
+  private void disposeAndRequestParentLayout() {
     Composite parent = this.getParent();
     this.dispose();
     if (parent != null && !parent.isDisposed()) {