Plasma5 - Black rectangle in top right corner on changing desktops

If I swap desktops, I am getting a large black rectangle. I only get this if I set the animation to Desktop cube:

Cannot get a screenshot as it is too quick…

It does not happen on the other animation methods - any one else seeing this?

I’ve noticed this, too. It’s a long-standing KDE bug, I think. Interestingly, it only manifests itself when you have a panel at the top of the screen. If it’s elsewhere (bottom, left, right), the rectangle does not appear!

My panel is on the left :slight_smile:

Edit - yup found it - https://bugs.kde.org/show_bug.cgi?id=372604

Hmmmm… I’ve just had a play around. A full size panel on the left does, indeed, provoke the glitch. However, if you “shorten” it a bit so that it does not actually touch the top of the screen, the glitch does not occur. What this means, I have no idea!!

Edit - There seems to be a suggestion >here< that it’s something to do with a rogue 640x480 window

I know this is an older post but it might help someone else looking for this.
In order to fix the annoying black rectangle you need to head to Desktop Effects -> Desktop Cube Animation -> Settings -> make sure “Do not animate panels” is disabled.

2 Likes

@vlad.isan thank you. I have same problem, but with your post resolve

Ps i’m running kde 5.10.1

thank you so much, this had been bugging me for quite a while!

Thank you vlad.isan!
I found that I had the same problem (similar actually: up-right quarter of the screen flashes on rotating the desktop cube) with the option
“Do not animate windows on all desktops”.
The problem appeared only when having gnome terminal (GTK apps?) at left-half of the screen (using “screen edge” placement), while having set it to be on all desktops (and activities).
When reducing the hight of gnome terminal, to less than the screen hight, there is no problem with desktop cube animation…
(In case it helps someone else…)