Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 452.06
Broken: version: 2.83.5, branch: master, commit date: 2020-08-19 06:07, hash: rBc2b144df395f
(I also tested in 2.9 beta, with the same result)
Worked: I don't know if it worked in earlier versions
Short description of error
Bone Constraints disappear after Undo. Specifically when you delete symmetrical bones with the "X-Axis Mirror" option ON, and then press Ctrl+Z.
Exact steps for others to reproduce the error
- Create a new single bone
- In Edit Mode, rename the bone to "Bone.L", move it a bit in the X-axis, and duplicate it.
- Constrain one bone to the other with any constraint, say "Copy Rotation"
- Symmetrize both bones. Now one bone on the left and one on the right has a Constraint.
- In Edit Mode activate the X-Axis Mirror option.
File in step 5:
- Delete Bone.R with Constraint on it.
- Press Ctrl+Z (which is very common because often you only want to delete the bone on one side but X-Axis Mirror will delete it on both sides).
- Go to Pose Mode and the Constraints on both sides should be missing.
If you keep pressing undo you can get to a state where the Constraints are applied. But if you keep working from step 8 above without realizing that the constraints have disappeared, then you may be unpleasantly surprised later on. I don't know if this can be explained with some features of the undo system. But it's definitely a bad user experience.