title control to not do unneeded work

src/vs/workbench/browser/parts/editor/sideBySideEditorControl.ts

@@ -220,8 +220,8 @@ export class SideBySideEditorControl implements ISideBySideEditorControl, IVerti
 			const titleAreaControl = this.getTitleAreaControl(position);
 			const context = this.stacks.groupAt(position);
 			titleAreaControl.setContext(context);
-			if (!context) {
-				titleAreaControl.refresh(); // clear out the control if the context is no longer present
+			if (!context && titleAreaControl.hasContext()) {
+				titleAreaControl.refresh(); // clear out the control if the context is no longer present and there was a context
 			}
 		});
 

src/vs/workbench/browser/parts/editor/titleControl.ts

@@ -45,6 +45,7 @@ export interface IToolbarActions {
 
 export interface ITitleAreaControl {
 	setContext(group: IEditorGroup): void;
+	hasContext(): boolean;
 	allowDragging(element: HTMLElement): boolean;
 	setDragged(dragged: boolean): void;
 	create(parent: HTMLElement): void;
@@ -174,6 +175,10 @@ export abstract class TitleControl implements ITitleAreaControl {
 		this.context = group;
 	}
 
+	public hasContext(): boolean {
+		return !!this.context;
+	}
+
 	public update(instant?: boolean): void {
 		if (instant) {
 			this.scheduler.cancel();