Add blur effect to widget panels as well

[Atak_Snajpera]

Currently it only uses simple transparency without any bluring effect like seen on taskbar

[Atak_Snajpera]

Also it would be nice if selected icon on desktop also had blurred background

Some wallpapers can be very busy so that change would nicely improve user experience.

[ngraham]

This was implemented recently, either in Plasma 6.3 or 6.4.

[Atak_Snajpera]

I’ve managed to fix this on my own. I also fixed inconsistency in shadow look. Now it uses the same style like in other panels (taskbar for example)