White header bar Twitter Profile Photo header bar is #F1F1F1 instead of dark gray in Firefox 26 and Seamonkey 2.22 on Win764bit.
It displays correctly in Chrome and Internet Explorer.
It's like this on freshly created default profile, or in safe mode.
It's the same using Windows Aero Theme, Window Basic theme, and Windows Classic theme.
I have tried to use Firefox's Tools/Web Developer/Style Editor and right-click Inspect Element to figure out where the color for this thing is and change it but I guess I'm not a web developer.
It seems like it might be a problem with transparency rather than color, but that's just a guess.
I know of one possibly similar problem with colors on Twitter.com in Firefox using Windows Classic theme regarding the background color of selected text in the Twitter search box. However that might only be similar in that it's a color problem in the same environment and not be relevant to what I'm asking about.