My system:

Linux gary 2.6.28-grml #1 SMP PREEMPT Tue Mar 3 12:43:54 UTC 2009
i686 GNU/Linux ... which is a Debian GNU/Linux unstable with
GKrellM v2.3.2

What I found out:

Whenever I switch from Notebook LCD (only) to external TFT (only) by
invoking ...

   xrandr --output VGA --mode 1680x1050 --output LVDS --off
   wmctrl -r gkrellm -e 0,1612,0,-1,-1
   (wmctrl changes placement of gkrellm due to different
   resolutions of internal LCD and external TFT)

... my gkrellm (with MonkeyLovers-theme) seems to lose its panel
setting: the other windows maximise over the full width and not only
until the border of GKrellM which is my intended and former setting.

Missing the panel setting does NOT mean, that the checkbox in the preferences
is not selected any more. The behavior changed, not more.

GKrellM still sits on top of all other windows but I am missing the
upper right corner of all maximised windows (my gkrellm is located
on the upper right corner of my screen).

The funny thing is, that this behavior does not apply to the default
theme nor to the theme called Modern. And when the error occurs
(e.g. GKrellM still on top but other windows maximise "behind"
GKrellM) it can be "corrected" by selecting another theme in the
GKrellM preferences.

When I am starting GKrellM with MonkeyLovers theme, it grabs its
panel state as expected and formerly maximised windows change its
sizes so that GKrellM gets its space in the upper right corner.

I was browsing through gkrellmrc and comparing it to the Modern
theme one but I could not find any setting what can cause this bug.

I wrote the original MonkeyLovers theme author Ron Rogers
<ash0xx@justballs.net> but his email address seems to be not existing
any more.