Board setup rows should be sortable when inserting new elements. They
get sorted when saving, this keeps that representation while editing
Fixes https://gitlab.com/kicad/code/kicad/issues/12015
A note to developers, please do not set the minimum and/or size of bitmap
buttons. It causes bitmaps to get clipped using GTK on Linux. If the
bitmap button size is not acceptable, then supply an appropriately sized
bitmap rather than attempt to force the wxWidgets sizing mechanism to do
what you want. This almost always causes platform differences that do
not work well.
Set the netclass grid a bit narrower so it doesn't end up with a scroll
bar.
Load the constraints bitmaps on show so they get drawn (otherwise all
but those in the first sizer are blank).