Sometimes part of window contents are not visible in
KDE Control Center, if the window is not big enough.
There are no scrollers drawn, but contents just go
out of view if the user reduces the window size.
I'm talking about the right half of the window, not the
tree selection on the left.
Select any component that has OK and CANCEL buttons
at the bottom and the reduce the height of the window.
The button will go out of view.