Set the titlebar faces for the various window states. In the current decor, use active-up as the face for the title bar when active and not pressed in. Use active-down when the title bar is active and pressed in, and inactive when the window is inactive. Both inactive and active-down default to active-up when not specified. Note that active-down will magically reverse the sense of the relief flag, so if your titlebar bar is raised in the active-up state, it will be sunk in the active-down state by default.