Created attachment 191978 [details]
screen shot before the bad screen size kicks in

I'm using Fedora 15, gnome-shell-3.0.2-4.fc15.src.rpm

When I first go to the activities screen, I see a dock on the left with icons for open applications, etc. and it shrinks the icons as I open more so that all are visible at once, as in the first screen shot.  But as soon as I try to look at the applications list, or any of various other things, the dock suddenly grows so that it sticks off the bottom of the screen.  Dock cons off the screen seem to be completely inaccessible.  The applications menu scrolls off the bottom of the screen and those entries are also inaccessible-- the bottom of the scroll area is off the bottom of the screen.  The icons in the middle of the screen are also scrolling off the bottom in the same way.  It's as if the shell has suddenly decided that the middle of the screen is much larger than it actually is.  This is *incredibly* annoying.  I'll post a second screen shot (I don't think bugzilla will let me post two at once?)