I found a little bug, that I can't replicate easily. I made a composite object, then attached a texture, then decided I didn't like the texture, so I hit Undo. Instead of returning to the previous colour (red), the model returned to white, even though the red colour is still in the settings.
The SH3D-file is here .
EDIT
To make it easier for you to find the bug: when reloading the file the colour returned to red, of course!
Hans