Click causes Player hang/freeze

I’m writing all of my actionscript in flex so to get the GUI, that was designed in Flash CS4, I have exported out the swf and load it in runtime.


var app:Loader = new Loader();
app.contentLoaderInfo.addEventListener(Event.COMPLETE, loadEvent, false, 0, true);
app.load(new URLRequest("interface.swf"));

Then I put the swf data into a movieclip and add that to the stage. If I add an event listener for a mouse click on any part of the GUI the whole application hangs for a full second. Any cause?