fix: Add layout refresher callback to ChatInputTextViewer for dynamic height adjustments

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

@@ -216,6 +216,20 @@ public ActionBar(Composite parent, int style, ChatServiceManager chatServiceMana
 
     ChatInputTextViewer tv = new ChatInputTextViewer(borderedActionBar, chatServiceManager);
     tv.setEditable(true);
+    // Relayout the chat view container so the new ActionBar preferred height is honored when the input grows or
+    // shrinks (e.g., recalling a long history entry with Up arrow, wrapping a long line, or clearing the input).
+    // Avoids a brittle fixed-depth parent traversal inside ChatInputTextViewer (see issue #215).
+    tv.setLayoutRefreshCallback(() -> {
+      if (ActionBar.this.isDisposed()) {
+        return;
+      }
+      Composite layoutTarget = ActionBar.this.getParent();
+      if (layoutTarget != null && !layoutTarget.isDisposed()) {
+        // TODO: An very interesting bug here, if we call layout(true, true), even no changes,
+        // The width of welcome view will become shorter and shorter, may investigate it later
+        layoutTarget.layout(true, false);
+      }
+    });
     tv.addTextListener(new ITextListener() {
       @Override
       public void textChanged(TextEvent event) {

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

@@ -58,6 +58,8 @@ public class ChatInputTextViewer extends UndoableTextViewer implements PaintList
 
   private Color placeholderColor;
 
+  private Runnable layoutRefreshCallback;
+
   /**
    * Constructs a new ChatInputTextViewer.
    *
@@ -77,6 +79,17 @@ public void setSendMessageHandler(Consumer<String> handler) {
     this.sendMessageHandler = handler;
   }
 
+  /**
+   * Registers a callback invoked after the input area's preferred height changes, so the owner can relayout the
+   * enclosing chat view container. This avoids a brittle fixed-depth parent traversal that breaks whenever the input
+   * area is rewrapped in a new composite (see issue #215).
+   *
+   * @param callback the layout-refresh callback; may be {@code null} to clear
+   */
+  public void setLayoutRefreshCallback(Runnable callback) {
+    this.layoutRefreshCallback = callback;
+  }
+
   public String getContent() {
     return this.getDocument().get();
   }
@@ -188,15 +201,24 @@ private boolean isInsertLineBreakOnly(TextEvent event) {
 
   private void refreshHeightLayout() {
     StyledText tvw = this.getTextWidget();
+    if (tvw == null || tvw.isDisposed()) {
+      return;
+    }
     // If the width is not initialized, use SWT.DEFAULT to compute the size
     // otherwise, swt will think that each line can only have one character.
     int widthHint = tvw.getSize().x == 0 ? SWT.DEFAULT : tvw.getSize().x;
     Point size = tvw.computeSize(widthHint, SWT.DEFAULT);
     GridData gd = (GridData) tvw.getLayoutData();
-    gd.heightHint = Math.min(tvw.getLineHeight() * MAX_INPUT_ROWS, size.y);
-    // TODO: An very interesting bug here, if we call layout(true, true), even no changes,
-    // The width of welcome view will become shorter and shorter, may investigate it later
-    ChatInputTextViewer.this.parent.getParent().getParent().layout(true, false);
+    int newHeightHint = Math.min(tvw.getLineHeight() * MAX_INPUT_ROWS, size.y);
+    if (gd.heightHint == newHeightHint) {
+      return;
+    }
+    gd.heightHint = newHeightHint;
+    // Delegate the relayout to the owner (e.g., ActionBar) so the chat view container reserves space for the
+    // updated input height.
+    if (this.layoutRefreshCallback != null) {
+      this.layoutRefreshCallback.run();
+    }
   }
 
   private void onKeyPressed(KeyEvent e) {