Hi there,
When I remove a texture (bitmap) from the diffuseslot which was applied to be seen in the viewport, it doesn't update and somehow seems to be cached to the object. The only thing to change this is to re-apply a new CoronaMtl
These steps reproduce the problem:
1. Create a box
2. apply a CoronaMtl with a random color
3. insert a bitmap in the diffuse slot and make it visible in the viewport
4. delete the bitmap by dragging an empty slot into the diffuse slot and you see that it remains in the viewport.
EDIT: added the line: by dragging an empty slot into the diffuse slot in line 4 for a proper representation of the error
The strange thing is that when you apply another shader and go back to the previous shader (the one with the deleted diffuse texture) the deleted texture shows up again as if it is cached.