OK used to save None for a corner tile the dialog showed as None because
the brush had no art or source for it, so that corner stopped drawing the
other kind of corner's art once the brush got some. It also copied the
art a corner borrows from the other kind of corner when that corner kept
its art. Now OK saves a corner tile's choice only when it was set from its
menu or with `ui.dialog.set`, or when the art it borrows goes away.
dotCooCoo
1c4894b2f7