If "Always on top" is enabled, the &xcenter; will always remain on top of all windows on the system. This is a "really-always-on-top" setting and will affect the entire system.

Hint: If you don't like this setting, assign an object hotkey to the &xcenter; on its "Icon" page. If you then press that object hotkey and the &xcenter; is already open, it will be resurfaced to the top of all windows.