DoubleClick on cotrols causes LoadingPanel Javascript error

[Forum]

var b=(!this._isSticky)?$get(this.get_element().id+k):this.get_element();
var i=new Date();
if(b==null){return;
}var j=i-b._startDisplayTime;
var f=this._minDisplayTime;
var e=new Telerik.Web.UI.AjaxLoadingPanelEventArgs(b,d);
this.raise_hiding(e);
if(!e.get_cancelNativeDisplay()){var a=this.get_animationDuration();
if(this._isSticky){if(f>j){window.setTimeout(function(){if(a>0){$telerik.$(b).fadeOut(a,function(){b.style.display="none";
});
}else{b.style.display="none";
}},f-j);
}else{if(a>0){$telerik.$(b).fadeOut(a,function(){b.style.display="none";
});
}else{b.style.display="none";
}}}else{if(f>j){window.setTimeout(function(){if(a>0){$telerik.$(b).fadeOut(a,function(){b.parentNode.removeChild(b);
});
}else{b.parentNode.removeChild(b);
}},f-j);
}else{if(a>0){$telerik.$(b).fadeOut(a,function(){b.parentNode.removeChild(b);
});
}else{b.parentNode.removeChild(b);
}}}}

I have a masterpage with a toolbar and RadAjaxManager control and the content page has the RadAjaxManagerProxy and RadAjaxLoadingPanel.  When users accidently double clicks the toolbar button, Loading panel wait screen shows up and Never goes away.  Single click works fine.  When I run this inside Visual Studio I get a JavaScript error message: JavaScript runtime error: Unable to get property 'removeChild' of undefined or null reference.  This is originating from the line: b.parentNode.removeChild(b). 
I am using version 2013.1.417.40. 

[Daniel]

Hello,

Can you please post your markup here so that we can try to replicate the problem?

Regards,
Daniel
Telerik