b617d6d5e6
Issue here is that we force mirroring even if original armature is not mirrored. We could be smart and store only unselected mirrored bones here (since those will get restored from transdata), however not all properties were getting stored and restored; rolling bones still suffered from the bug for instance. To fix this we need to restore all properties that armature mirroring overrides. Transdata obviously does not offer a lot of space here, so I used TransInfo->customdata to store an array of initial parameters of the mirrored bones.