This might be an issue with IE's debugger; developer tool item as opposed to a jq bug.
Context: IE (All Version), Windows (XP & 7), JQ Version: 1.9.1, 1.8.3 (and 1.7.2)
Expected: Dialog-Modal shows after debugger on line 4, like it does on non-IE browsers (using developer tools->scripts).
Observed: Dialog-Modal doesn't show until after line 11 in IE, regardless on the length of the function that calls it using developer tools->scripts->start debugging).
In real practice, it's not usually a big deal, but when you're chaining functions together and a monstrous data piece, IE would look like it hangs on click, because regardless of where you call it in the stack, it doesn't execute until the stack is cleared out, which means it'll be waiting however many cycles until all related action code is finished.
But then again, it could be IE holds all dom element modifications in debugger; scenarios until the end (which I tested, and it does the same with width at the very least), which I wouldn't hold past IE to do something like that.
All behavior i've tested initially that I've pared off has indicated otherwise, as I'm not using ajax in my main scenario, and so, I started testing with Debugger to try to find out when exactly the UI Dialog box opened, and tried to figure out when exactly the UI Dialog displays, but then I moved away from trying to show it with .dialog("open"), and then went straight to .show(). When I use debugger, the default answer in IE has been: always at the end of the function stack. When I don't use it, I can't accurately tell you, but it seems like it follows the same path.