diff --git a/src/vs/base/browser/ui/checkbox/checkbox.ts b/src/vs/base/browser/ui/checkbox/checkbox.ts
index a643e9f86a9..6f76a164a4f 100644
--- a/src/vs/base/browser/ui/checkbox/checkbox.ts
+++ b/src/vs/base/browser/ui/checkbox/checkbox.ts
@@ -40,7 +40,7 @@ export class Checkbox extends Widget {
 	constructor(opts: ICheckboxOpts) {
 		super();
 		this._opts = objects.clone(opts);
-		objects.mixin(this._opts, defaultOpts);
+		objects.mixin(this._opts, defaultOpts, false);
 		this._checked = this._opts.isChecked;
 
 		this.domNode = document.createElement('div');
diff --git a/src/vs/editor/contrib/zoneWidget/browser/peekViewWidget.ts b/src/vs/editor/contrib/zoneWidget/browser/peekViewWidget.ts
index 2f742f71f38..4754a395e3c 100644
--- a/src/vs/editor/contrib/zoneWidget/browser/peekViewWidget.ts
+++ b/src/vs/editor/contrib/zoneWidget/browser/peekViewWidget.ts
@@ -76,7 +76,7 @@ export abstract class PeekViewWidget extends ZoneWidget implements IPeekViewServ
 
 	constructor(editor: ICodeEditor, options: IPeekViewOptions = {}) {
 		super(editor, options);
-		objects.mixin(this.options, defaultOptions);
+		objects.mixin(this.options, defaultOptions, false);
 	}
 
 	public dispose(): void {
diff --git a/src/vs/editor/contrib/zoneWidget/browser/zoneWidget.ts b/src/vs/editor/contrib/zoneWidget/browser/zoneWidget.ts
index 76706034b0d..fc879818268 100644
--- a/src/vs/editor/contrib/zoneWidget/browser/zoneWidget.ts
+++ b/src/vs/editor/contrib/zoneWidget/browser/zoneWidget.ts
@@ -119,7 +119,7 @@ export abstract class ZoneWidget extends Widget implements IHorizontalSashLayout
 		super();
 		this.editor = editor;
 		this.options = objects.clone(options);
-		objects.mixin(this.options, defaultOptions);
+		objects.mixin(this.options, defaultOptions, false);
 		this.domNode = document.createElement('div');
 		if (!this.options.isAccessible) {
 			this.domNode.setAttribute('aria-hidden', 'true');