Sometimes I need to inspect elements that are only showing up on a page if you put mouse over some area. The problem is that if you start moving mouse towards firebug consol
You can also start the debugger on a timer. Enter this command into the console:
setTimeout(function(){ debugger; }, 10000);
This will give you 10 seconds to use the mouse and make the page look the way you want in order to inspect it. When the debugger starts, the page will freeze, and you'll be able to explore the elements in the developer tool tab, without the DOM changing or responding to any additional mouse events.