XnView Software

XnView: MP 1.3.1 64bits
OS: Windows 64bit (22H2), display resolution 3840x2160, win scaling 150%

Viewer mode, Image → Rotate → Rotate...
unticking 'Apply to image' does not reveal original image

To reproduce:
1. run clean portable XnViewMP
2. open image
3. goto Image → Rotate → Rotate...
4. change Angle to any value
5. tick 'Apply to image' checkbox
image will reflect changes
6. untick 'Apply to image' checkbox
image will not return to original state

Expected behaviour:
unticking 'Apply to image' shall reveal original image

not sure, the image reveal to original only when clicking on 'cancel'

This is just common behaviour in the program - if 'Apply to image' is unticked image - return to original state.
Guess behaviour can be changed if instrument has cumulative_effect/multiple_iterations, but this is not the case here.