STEPS TO REPRODUCE
1. Launch Character Creator
2. Navigate to Menu > Create > Morph Slider
3. On Morph Slider Editor panel, change the settings as blow:
Set Category: Body
Set Slider Path: Full Body/t1
Morph Name: t1
Source Morph: Default Morph
Target Morph: File (Load a OBJ file to program)
4. Click "OK" button on the panel
5. Click to delete the new created Morph Slider
6. Click "Undo" on Toolbar

ACTUAL RESULT
It won't record "Undo/Redo" action if delete the Morph Slider

EXPECTED RESULT
It will record "Undo/Redo" action if delete the Morph Slider