Tracking down accessibility issues and providing solutions

Hi All
 
I've just been looking at the latest DNN default website installation with a
view to using DNN as a CMS - you can look at this at:
 
http://dnnw2012.cloudapp.net/Community.aspx
 
One thing that I notice is that the submenu item off the About Us menu item
which is displayed when the mouse hovers over the About Us menu isn't
accessible via the keyboard alone. It is accessible however via the keyboard
while the mouse is hovered over the About Us menu item when the Style Guide
submenu item is shown.
 
This to me seems like a simple problem to resolve. simply show the submenu
item when the About Us menu item receives focus and all should be well.
 
DNN is open source so I thought I'd modify the appropriate script file to
run the same code as the mouseover function uses when the menu item receives
focus and feed this back into the source. So I open firebug and look at the
offending element which brings me to my point. 
 
The HTML is nice and clean and I couldn't see anything obvious going on in
the related CSS for the menu link and so I assume a script is being used to
perform this function.
 
However, DNN uses numerous scripts and external libraries such as jQuery-UI,
some of which are likely to be minified as well. Quite frankly without
getting into the framework I haven't got a clue where to start looking.
 
Obviously one option is to raise this with the community and let them sort
it out but who knows how long that might take. Furthermore, it's entirely
possible that the issue is with one of the external libraries and so the
issue may never even reach those who could fix it. 
 
So i thought I'd ask if anyone has any ideas or uses any tools which could
help to quickly isolate the code being used to display the popup menu and
where it is being initiated? Even if it turns out that modifying the source
is going to be more complicated than it would appear to be, at least then I
know who exactly to raise this with and can explain where they need to look
to resolve the issue.
 
I do appreciate that this kind of approach isn't always going to be viable
and there's still the issue of how to push changes back into the main source
for testing and later release. But for those who feel they could contribute
positively by modifying source code, it would be great to have the tools to
quickly isolate these kind of issues.
 
I'm not an expert firebug user by any means and maybe there is a way to do
this using firebug or maybe I'm expecting too much from the browser. What I
am asking here is a way to find out where the function fired by the
mouseover event for that element is initiated.
 
However,  any thoughts or suggestions would be appreciated.
 
Cheers
Ian