So far, when the toolbar was visible, the tool settings header would show empty
space instead of the tool icon. This was probably to avoid jumping of the
layout. However this empty space looks quite jarring, and alignments in that
corner are all over the place with it (causing visual noise). On the other hand
the jumping seems like a minor problem, it's quite subtle, esp since the
viewport overlay text does a similar jump. Having the icon appear and disappear
based on the toolbar visibility also causes visual distraction, so the problem
was mitigated at best.
Pull Request: https://projects.blender.org/blender/blender/pulls/112972
060634e611