I don't think you can make the title bar colour change dynamically as it does with Firefox, but it is possible to change it manually with a userChrome.css file.

One way is to install Stylish in TB, then create a new style using the CSS from here.

Thanks for the info about Stylish. I'm not trying to have any special control over the TB title bar, I just want it to look like every other title bar on my computer. Is there something about TB that prevents it from utilizing the default windows title bar color?

I don't know why TB doesn't work like most other applications, but I suspect it depends on some core elements in Firefox being modified first, for which there are bugs under current discussion. The Stylish method is simply a stopgap measure until these bugs are resolved and incorporated into TB.