Fix placement blueprints not being correctly removed after a rolled back placement
This isn't required but makes the initial appearance animation nicer.
Update timeline control point display
Doesn't make a huge difference but this was intended.
Gives it a bit more visibility. This is where it was meant to sit, but didn't consider using a proxy drawable to make it work previously.
Update timeline slider/spinner apperance
Fix ctrl-dragging on an existing selection unexpectedly causing deselection
Closes #12042.
Co-authored-by: Bartłomiej Dach <dach.bartlomiej@gmail.com>
Reverse()
Co-authored-by: Dan Balasescu <smoogipoo@smgi.me>