Blender Git Loki

Fix T39911: Unpredictable behaviour when editing y-coordinate of right handle via Active Key panel (for aligned handles)

Editing the y-coordinate of the right handle of a keyframe via the Active Keyframe
panel in the Graph Editor, while both handles are selected and are both of type "aligned"
resulted in weird behaviours such as the x-coordinate of the right handle changing
(and rapidly starting to overshoot) but nothing else. However, this problem
doesn't occur when only a single handle is selected.

It turns out that the "order of computation" logic in calchandleNurb_intern() gets
confused in the case of both handles being selected, and results in a sub-optimal
handling of the right handle being the one that's been changed. We hack around this
here by temporarily making it so that just the right handle is selected when doing
the updates here.