Bug: Image plane scale not persistent on save/reopen

[pfalkingham]

Bug Description

When adjusting the scale of an image plane in the XROMM Blender Tools addon, the scale value is not saved with the .blend file. After saving and reopening the file, the image plane reverts to its original/default scale.

Steps to Reproduce

1. Load XROMM data in Blender using the XROMM Tools addon
2. Adjust the scale of an image plane
3. Save the .blend file
4. Close and reopen the .blend file
5. Observe that the image plane scale has reverted

Workaround

Moving the image plane at all after reopening triggers the scale to update to the correct value.

Expected Behaviour

Image plane scale should persist across save/reopen cycles, just like other object properties.