Comment 24 for bug 30146

I think I've figured out why the package manager seems to trip it up. It presents a unique case, where both the contents of /usr/share/pixmaps and /usr/share/applications change at the same time, or at least in between menu browsing.

Here's an example that I've found to rigorously reproduce this bug:
0. (Gnome ,menu must be on bottom panel.)
1. Browse menu until bug no longer is present.
2. sudo cp /usr/share/applications/totem.desktop /usr/share/applications/test.desktop
3. sudo touch /usr/share/pixmaps/test.png
4. Browse menu and notice that the bug appears

The important thing is that you don't browse the menu in between steps 1 and 4, because just doing either step 2 or step 3 does not seem to produce the bug. Just when both happen in between menu browsing does it occur. Also, steps 2 and 3 can be performed in reverse order, i.e. step 3 then step 2. And also, it seems that to reproduce this, it needs a real ".desktop file" in the applications directory, whereas a phony touch'ed png file will suffice (although so will a real image) in triggering the bug.

And, of course, to reproduce it again:
1. Browse menu until bug is no longer present
2. sudo rm /usr/share/applications/test.desktop
3. sudo rm /usr/share/pixmaps/test.png
4. Browse menu and notice that the bug appears