I want your help to try a bug, it's depend perhaps of graphic cards, so try and says if the bugs happens and your graphics card, the bug was found by poutsa :
Follow this Steps to see it:
Select the Cube from Starting Scene!
Enter Edit Mode and Select all Vertices
Then Go to Editing Buttons F9 and add a New Vetex Group (group) and press Assign!
Then Exit from Edit Mode and go to Weight Paint mode
Then go back to Object mode and you see the Cube is Rosa Colour in Open GL Draw mode!!
After this go to File Menue and and choose NEW ...erase All so you see the New Sarting Scene the Cube is Rosa Colour again in Open GL mode!
I have a Nvidia Geforce 5800 and I have the bug.
I have also verified this bug. I have a Geforce 5900XT. The steps I took to create this bug are as follows:
With any mesh
1. Enter weight paint mode.
2. Color the whole mesh a certain weight color
3. Enter object mode
4. Now the mesh is the same color (tint) of what you painted in weight paint mode.
5. Now go to File->New. The default mesh object will have the same tint.
6. If you totally exit out of blender and the start a new session, the object will be the correct color.
As far as I can tell the object that you paint(completely) in weight paint mode will receive a tint of the color you painted.
Thanks,
pixeltroll