Please describe the problem:
When the user clicks any menu in the Gnome menu bar for the first time in a
session, the icons are not in cache, so the menu is displayed first and the
icons filled in afterward.  Because this changes the size of the menu items, the
menu must expand.  If it's at the top of the screen, it expands downward.  If
it's at the bottom of the screen, it instead hides part of the menu and shows
scroll buttons.

Steps to reproduce:
1. Make sure icons are on in the Applications menu, and that they're larger than
the text.
2. Log out and log in again to clear the icon cache.
3. Put the menu bar at the bottom of the screen.
4. Click the applications menu.


Actual results:
Part of the menu is hidden, and scroll buttons appear, even though the menu is a
small fraction of the screen height.

Expected results:
I would expect GNOME to remember the sizes of the icons in its menus when laying
out the menu the first time, even if they have not loaded yet.  Failing that, I
would expect the menu to expand (upward) when the icons become available.

Does this happen every time?
Yes.

Other information: