Description of problem:
The contextual menu for mozilla products like thunderbirs and firefox get hidden by the top black bar of gnome shell.

Version-Release number of selected component (if applicable):
a) Linux localhost.localdomain 3.9.2-200.fc18.x86_64 #1 SMP Mon May 13 13:59:47 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
b) gnome-shell-3.6.3.1-1.fc18.x86_64
c) thunderbird-17.0.6-1.fc18.x86_64
d) firefox-21.0-3.fc18.x86_64

How reproducible:
With thunderbird always
With firefox not all the times

Steps to Reproduce:
1.Open thunderbird
2. hit new message
3. write a word wrong that has several options for spelling
4. right click on the word that has red underline saying that is mispelled

Actual results:
The top option, usually the most useful is hidden behind the top bar of gnome shell, if you get the mouse over, you can see a very thing blue line and you can actually select that word.

Expected results:
The top option to be below the top black bar of gnome shell.

Additional info:
You can see pictures of the problem in my blog, so you can have a clear idea of the problem. My blog is in Spanish, but you can look at the images anyway.

http://www.taygon.com/?p=810