Fixes microsoft#171170 (microsoft#185561)

Author: hediet

src/vs/workbench/contrib/mergeEditor/browser/view/fixedZoneWidget.ts

@@ -6,6 +6,7 @@
 import { h } from 'vs/base/browser/dom';
 import { Disposable } from 'vs/base/common/lifecycle';
 import { ICodeEditor, IOverlayWidget, IViewZoneChangeAccessor } from 'vs/editor/browser/editorBrowser';
+import { Event } from 'vs/base/common/event';
 
 export abstract class FixedZoneWidget extends Disposable {
 	private static counter = 0;
@@ -41,7 +42,9 @@ export abstract class FixedZoneWidget extends Disposable {
 		});
 		viewZoneIdsToCleanUp.push(this.viewZoneId);
 
-		this.widgetDomNode.style.left = this.editor.getLayoutInfo().contentLeft + 'px';
+		this._register(Event.runAndSubscribe(this.editor.onDidLayoutChange, () => {
+			this.widgetDomNode.style.left = this.editor.getLayoutInfo().contentLeft + 'px';
+		}));
 
 		this.editor.addOverlayWidget(this.overlayWidget);