This may happen if the windows style is 'Aero Glass' instead of 'Aero Basic'. It's possible you set the system theme color but it could be appear real light so as to make it difficult to tell it changed at all. To this end, I think you want to use the WIN32API call SetSystemVisualStyle (uxtheme.dll) I believe that's what you're after, how to change the windows color theme/scheme. I don't think the color of the task bar has any correlation with an application, and that it is a system-wide setting (or more correctly, user-wide). To change the color of the whole taskbar (I'm assuming you're talking windows 7 or later), you have to change the windows visual theme color, such as can be done through Control Panel->Personalization->Color and Appearance.
