don't read null range, #46893

src/vs/editor/contrib/zoneWidget/zoneWidget.ts

@@ -210,6 +210,7 @@ export abstract class ZoneWidget implements IHorizontalSashLayoutProvider {
 		}
 
 		this.editor.deltaDecorations(this._positionMarkerId, []);
+		this._positionMarkerId = [];
 	}
 
 	public create(): void {
@@ -280,10 +281,14 @@ export abstract class ZoneWidget implements IHorizontalSashLayoutProvider {
 
 	public get position(): Position {
 		const [id] = this._positionMarkerId;
-		if (id) {
-			return this.editor.getModel().getDecorationRange(id).getStartPosition();
+		if (!id) {
+			return undefined;
 		}
-		return undefined;
+		const range = this.editor.getModel().getDecorationRange(id);
+		if (!range) {
+			return undefined;
+		}
+		return range.getStartPosition();
 	}
 
 	protected _isShowing: boolean = false;