Other in KDE Base
Don't force that the preview size must be >= the icon size. This gets confusing when the user uses the Zoom In/Zoom Out feature inside a view a lot (e. g. by Ctrl + scroll wheel).
This is because decreasing the preview size would also decrease the icon size, but when increasing the preview size again the icon size remains...
I even got confused myself by this "feature" although I knew the reason for it ;-)