[DevTools] Listen to mousedown in SoftContextMenu once

third_party/WebKit/Source/devtools/front_end/ui/GlassPane.js

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 UI.GlassPane = class {
   constructor() {
     this._widget = new UI.Widget(true);
     this._widget.markAsRoot();
     this.element = this._widget.element;
     this.contentElement = this._widget.contentElement;
@@ skipping 105 matching lines @@
   }
 
   /**
    * @param {!Document} document
    */
   show(document) {
     if (this.isShowing())
       return;
     // Deliberately starts with 3000 to hide other z-indexed elements below.
     this.element.style.zIndex = 3000 + 1000 * UI.GlassPane._panes.size;
-    document.body.addEventListener('click', this._onMouseDownBound, true);
+    document.body.addEventListener('mousedown', this._onMouseDownBound, true);
     this._widget.show(document.body);
     UI.GlassPane._panes.add(this);
     this._positionContent();
   }
 
   hide() {
     if (!this.isShowing())
       return;
     UI.GlassPane._panes.delete(this);
-    this.element.ownerDocument.body.removeEventListener('click', this._onMouseDownBound, true);
+    this.element.ownerDocument.body.removeEventListener('mousedown', this._onMouseDownBound, true);
     this._widget.detach();
   }
 
   /**
    * @param {!Event} event
    */
   _onMouseDown(event) {
     if (!this._onClickOutsideCallback)
       return;
     var node = event.deepElementFromPoint();
@@ skipping 242 matching lines @@
 UI.GlassPane.MarginBehavior = {
   Arrow: Symbol('Arrow'),
   DefaultMargin: Symbol('DefaultMargin'),
   NoMargin: Symbol('NoMargin')
 };
 
 /** @type {!Map<!Document, !Element>} */
 UI.GlassPane._containers = new Map();
 /** @type {!Set<!UI.GlassPane>} */
 UI.GlassPane._panes = new Set();