The tab widgets are being redrawn like crazy under some conditions.
For example, lots of scrolling output from shell mode in window 2 is
causing the tab widgets to flash like crazy.
Not sure yet precisely how to reproduce it - but I've seen it several
times after just seconds of use - so it's not too hard.
Ditto here. Also the gutter tends to not get drawn at all when it is not
flashing crazily. To repro here (linux, XFree86, WindowMaker 0.60) all I
have to do is hit 'C-l' to refresh the screen and the tabs disappear. It
comes back if I split the window (C-x 2 or 3), but disappears again as soon
as I hit C-l