How to make the panel height less than 28 pixels in KDE 6?

When I edit the panel I can’t make the height 22px. The height is reset to 28 px

I managed to overcome the problem by switching the global theme to Breez, and I separately connected the color palette and window design from the theme I needed

Yup, minimum panel height is determined in part by the roundness of the corners of your Plasma theme. With a theme that has 14px corners, a panel less than 28px thick would have visual glitches.