I give my english a shot.

to the question.
i use slackware 9.0 and openbox as my windowmaker.
and i wanted to start gkrellm whitout the border of top of it like the one you always have in windows for exampel whit the X ( close ) and minimise and every thing. hope you understand me.
so i start gkrellm whit gkrellm -w and the border is gone and its nice.
but now to the problem whit mozilla. when i start mozilla the mozilla windows starts next to the gkrellm window so i have to drag the mozilla window over the gkrellm to get it into fullscreen. this is very anoying and i need help to fix so mozilla will start on top of gkrellm not beiside it.

thats all

Did you ever think about trying the command

man mozilla


Mozilla options
-height value
Set height of startup window to value.

-h, -help
Show summary of options.

-installer
Start with 4.x migration window.

-width value
Set width of startup window to value.

Also which window manager are you using?

Some window managers try to be smart and try to prevent
windows overlapping.