STEPS TO REPRODUCE
1. Launch iClone 6
2. Navigate to Content Manager > Stage > ImageLayer > Image, apply two random content, such as: Air Fight and Car
3. Go to Scene Manager, click ImageLayer(0)
4. Navigate to Modify > Edit > Image Layer > Layer Order, click "Move Backward"
5. Go to 3D view, pick the Image Layer, move it to the right
6. Click "Undo" on Toolbar

ACTUAL RESULT
The Scene Manager appeared a extra image layer unexpectedly

EXPECTED RESULT
No extra Image Layer created