rem: if (aEvent.button != 0 || aEvent.target.getAttribute("anonid") != "button") return; 
add: /** * 1. Only left click starts the click and hold timer. * 2. Exclude the dropmarker area. This is done by excluding *    elements which target their events directly to the toolbarbutton *    element, i.e. when the nearest-parent-element which allows-events *    is the toolbarbutton element itself. * 3. Do not start the click-and-hold timer if the toolbarbutton is disabled. */ if (aEvent.button != 0 || aEvent.originalTarget == aEvent.currentTarget || aEvent.currentTarget.disabled) return; 
context: function ClickAndHoldMouseDown(aEvent){ if (aEvent.button != 0 || aEvent.target.getAttribute("anonid") != "button")   return; // relying on button.xml#menu-button-base internals for improved theme compatibility var button = aEvent.target._menubuttonParent; if (!button.disabled)   gClickAndHoldTimer = setTimeout(ClickAndHoldMouseDownCallback, 500, button);}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/b6abc0241cc67d42af49c52160ba4c6af920cc36/browser.js/buggy/browser/base/content/browser.js