The attached image shows what I mean. This not occur with java based programs.
My video card is nvidia and have worked very well in the past.
Now I dont remind what I did that could cause this issue...
The program in the image is filezilla, but malfunction occur with firefox too.
I use kde (linuxmint)
Thanks.-

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I do not know for certain what is wrong, but there are two possibilities I am thinking of:

First, have you changed any settings in KDE recently? Sometimes menus, windows, and so forth are affected by configuration settings in your desktop environment.

Second: I believe that FileZilla and Firefox are both dependent on the GTK widget libraries. Which versions of gtk+ and glib are installed on your system? Perhaps upgrading software may help.

If there is anything else you have changed or reconfigured on your system recently, you should describe it. Also, are there any other applications on your system that are behaving this way? Also, can you install another desktop environment (for example, Gnome or Xfce4) and see if the problems occur while using it? These are ideas that might help narrow down the problem.

It's fairly simple to create a new user account and log into it. If the problem does not occur in that test account, then the cause of the problem is somewhere in your KDE settings at ~/.kde

This would help rule out things like missing packages or hardware errors.

LOL LOL LOL LOL LOL!
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Thanks for your suggestions. Yes, it is sure that my problem is related to KDE settings.
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But you know? the old and trusty XFCE is running as usual at speed of light.
I'll adapt it again for a while (malfunction not presented here .
Cheers...
NomikOS.-