Apologies if this is a feature that's not yet implemented rather than an actual bug. Happy to change this into a feature request indeed :)
Link to .capx file (required!):
Steps to reproduce:
1. Open project.
2. Edit the only sprite on the layout (there is only one frame of animation)
3. Click the 'Set origin and image points' button.
4. Change the location of the origin point.
5. Press Ctrl-Z.
Origin/image point change is not undone/reversed.
Origin/image point location change is undone to the prior location.
Chrome: N/A - Editor.
Firefox: N/A - Editor.
Internet Explorer: N/A - Editor.
Operating system & service pack:
Windows 7 x64 SP1.
Construct 2 version:
R152 64 bit.