Hi all,
I solved my problem by starting Openoffice this way, i.e. calc:
ooffice2 --widgets-set qt -calc %U
This way Openoffice's window is indeed grey (= does not use system-colors, but I don't mind), but does not look ugly and the "paper" is white and all colors are shown
You can play with setting the widgets-set by using qt, gnome, gtk or kde.
You can also set the "export OOO_FORCE_DESKTOP=gnome" in i.e. .bash_profile (allthough I use KDE) - you can start Openoffice from console then.
I set --widgets-set qt in every menuentry of Openoffice and it works fine when I open a file in konqueror.
BTW, by searching through internet I found out, that there are not many, but some people with this problem and they are not default to Linux. There are Windows-users as well as Linux-users of all kind of distributions and in there KDE-, Gnome- and Other-users, but far to less that somebody could provide a usefull solution or even has an idea why it happens.
HTH,
Yanaar