Gkrellm has some nice features, but, when it is (accidentaly?) selected (with alt-tab or something simmilar) and then someone presses PgUp/PgDown button (to do something else) the theme is changed (in my case from pretty transparent theme, to some other ugly theme). Usually, because it runs in the background, behind other windows, you notice this when it's too late, and have to cycle thru the themes to find the one you like again.
I dont know why, but the hotkeys were hardcoded in gkrellm, so, to change them, you have to actually patch the source.
I've changed the PgUp/PgDown hotkeys to Shift+PgUp an Shift+PgDown (but this can easily be changed by editing my patch
The patch still works on gentoo's gkrellm-2.3.2, and should work with simmilar versions. If not, it shoud point out to where the changes should be made to change the hotkey assignment.
Click here to download the .patch file