I added this to the bug tracker, but here is a repost. Maybe there is an easy fix.

When right clicking and changing the toolbox icon sizes in Krita 3.0 Beta, the image icons remain normal (small) scaled, but the tile/box around the icons increase. The icon of the tool itself is unchanged. The feature worked previously as I used to increase the toolbox icons to use with my surface pro. The feature now seems to be broken.