Switching window focus causes stuttering
Switching focus from one window to another causes severe stuttering for a second or so. To see this better try to drag inactive window and immediately move it around the screen.
The issue persist only in X11 session (I use Nvidia proprietary driver and KDE 5.24.4) and does NOT occur in Wayland. If you disable window shadow by setting Shadow Size to None in Window Decoration then the issue also does NOT occur.
Another workaround if you open breezedecoration.cpp, go to void Decoration::updateShadow()
and remove these lines. Or use any other window decoration theme that doesn't animate shadow for active/inactive windows.
// Animated case, no cached shadow object
if ( (m_shadowAnimation->state() == QAbstractAnimation::Running) && (m_shadowOpacity != 0.0) && (m_shadowOpacity != 1.0) )
{
setShadow(createShadowObject(0.5 + m_shadowOpacity * 0.5));
return;
}
After a bit of googling I found some threads related to this. It looks like this bug is very old.
Edited by Ghost User