First: admission: I still use twm. Or, rather: twm has been my fallback window manager for years, when other X setup breaks. As it so often does.
Instead of the widgets at the top of my windows being nice and compact:
They were "blown up":
This was particularly painful when working on my tablet PC, 1366x768. Too much screen space lost. Got in the way of doing useful work.
I have avoided the problem all this time, 8 months, by not using my laptop except when plugged into external monitors with lots of pixels.
Well, this week I away from my external monitors. So I figured out what the problem was.
By process of elimination:
The problem that was causing the twm RightTitleButtons to be too large was due to
When I unset LANG, or set LANG=C (as I have had to do elsewhere), twm works properly.
Why? I dunno.
Why do I have LANG set to en_US.UTF-8? I dunno - it was default.
glew@ubuntu-uarch:~$ uname -a
Linux ubuntu-uarch 2.6.32-33-generic #72-Ubuntu SMP Fri Jul 29 21:07:13 UTC 2011 x86_64 GNU/Linux
But also occurred on CentOS and RedHat.
Some text that might make it easier to find this bug and fix:
X widgets bad sizes
in twm RightTitleButton
due to LANG=en_US.UTF-8
fixed by unsetting LANG or setting LANG=C