Relates to #162 (closed) and #175 (closed)
This branch is in good shape now.
Known issue: if you change the scale to 0.8 it succeeds. If you then try to directly go back to 1.0 it fails. If you switch to some intermediate scale like 1.4 and then back to 1.0 it works.
Haven't been able to figure out what in the state machine is broken there...