The Bluebottle Window Manager allows concurrent drawing to many possibly semi transparent windows that can be freely positioned. The window manager supports XML definable styles as well as style plug-ins.

The window manager defines a coordinate space in which the windows are positioned. One or more coordinate space observer (called "view") can be installed. Each "view" represents one display adapter, VNC server or other coordinate space observing application such as a screen shot utility or "movie recorder". The views can be freely positioned.

• Thomas Frey, Bluebottle : A Thread-safe Multimedia and GUI Framework for Active Oberon, PhD thesis, Institute of Computer Systems, ETH Zurich, 2005 (pdf)

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