Use MultiPageEditorPart for getting active editor

Author: SougandhS

team/bundles/org.eclipse.compare/compare/org/eclipse/compare/internal/ClipboardCompare.java

@@ -46,7 +46,8 @@
 import org.eclipse.ui.IWorkbenchPage;
 import org.eclipse.ui.IWorkbenchPart;
 import org.eclipse.ui.PlatformUI;
-import org.eclipse.ui.forms.editor.FormEditor;
+import org.eclipse.ui.part.EditorPart;
+import org.eclipse.ui.part.MultiPageEditorPart;
 import org.eclipse.ui.texteditor.ITextEditor;
 
 public class ClipboardCompare extends BaseCompareAction implements IObjectActionDelegate {
@@ -102,8 +103,11 @@ private void processComparison(Shell parentShell) throws IOException, CoreExcept
 			return;
 		}
 		final String selectionContents;
-		if (editor instanceof FormEditor fromEditor) {
-			editor = fromEditor.getActiveEditor();
+		if (editor instanceof MultiPageEditorPart mpe) {
+			Object page2 = mpe.getSelectedPage();
+			if (page2 instanceof EditorPart e) {
+				editor = e;
+			}
 		}
 		if (editor instanceof ITextEditor txtEditor) {
 			ISelection selection = txtEditor.getSelectionProvider().getSelection();