Text Color On Tabs Doesn’t Stick

I use dark colors on my tabs, and I set the text to white. However, every time I restart Firefox, the text color reverts to black. When I go into the options menu, the color is still set as white even though it displays as black. I have to change the color to something else, close the window and then go back in and change it to white again. It would be great if you could make the color stick, so I wouldn't have to go through this routine every time I restart. Thanks!