With "keep panel below windows" set, when I bring up the foot menu, it still (reasonably and appropriately) pops up above other applications, but the panel drawers stay below and invisible. At least when panel drawers are set to collapse automatically when an application is invoked, and maybe always, I would suggest that they should, like menus, be on top of other applications.
The current panel defaults to being on top, not on the bottom, so this doesn't come up. The problem with the suggestion is one of geometry - the drawer is animated as coming out beneath the panel and it doesn't work to have the panel is below all other windows, the drawer below the panel, and the drawer on top of all other windows... It would be possible I suppose to make the drawer not be below the panel, or to change after the expansion...
Changing after the expansion would certainly satisfy me...
Does this bug still exist?
This issue was brought up with the panel hackers, and they decided to keep the present behaviour.