[SOLVED] gtk under KDE: artifacts and window redraw problems

[freifunk_connewitz]

hi,

I'd appreciate any help in solving a graphics problem that started a few months ago.

Some applications started to show window redraw and font problems. Especially thunderbird is affected, but that could just be my impression because I use it every day.

Description of the thunderbird redraw problem:
1) after a while working with it, especially often after switching back to thunderbird from other open windows by using alt-tab, parts of the thunderbird window are completely black - the account list, the message list, the message pane, the menu, it can affect all window elements. they reappear if I move the mouse over them. this does not apply for static window elements like the separators between buttons, they remain black. I get the whole window back completely only through maximizing and again resizing it. this is what happens almost all of the time if I use thunderbird for more than five minutes.
2) a second problems affects the message pane of compose-windows. there, it happens from time to time that the entered text will just disappear. I it still there but it is not shown anymore. I get it back through scrolling it out of and back into sight.
3) as already described here: [SOLVED]characters messed up in firefox, thunderbird, office, sometimes letters just disappear. if that happens, every menu entry, message title in the message list, or even the message text miss certain letters. there was no clear logic which ones, most of the time also very common ones like the 'a' or the 'e' so that not much except 't's and 'n' were left. It's just as if most of the letters of a word have the same color as the background - the word "gentoo" could look like " nt ". The character problem, however, happens only seldomly.

It is not only thunderbird that is affected by these problems. Also gtkmm, pinentry or libreoffice sometimes had problems to redraw their windows when focus came back to them. The missing letters problem - if it occurs - affects all non-KDE / non-Qt applications.

NOT affected are all KDE applications / menus / windows and opera.

When it happens, there are no error messages in /var/log/messages.
The only errors thunderbird printed where:

[freifunk_connewitz]

hi again,

ok, if >100 people have read it and nobody has had a clue that sounds as nobody has ever encountered anything vaguely similar.

but even then, I need your opinion, please: would you rather suspect

a) a hardware issue with the integrated intel-core-i5-graphics or with memory? that's what one could think because it always only happens after a while working; or
b) some old configuration lurking in the background (I've set up this machine about 5 years ago); or
c) KDE's gtk integration needing some clean up?

[freifunk_connewitz]

seems to have been b) and c)

I deleted my ~/.kde4-folder and re-logged in. after a few days of testing thunderbird and all other gtk-applications behave and look like they are expected again. maybe there have been some vital changes in KDE's core system that do not go along well with older configurations.

so, if anybody encounters a problem like mine, this should be your solution, too. marking solved.