BUI is the windowing environment for BeagleBox that is originally based on a stripped down version of Matchbox. It is a separate project from BeagleBox that can be built outside of the BeagleBox build. BeagleBox simply pulls the latest version of BUI from the SourceForge releases.
BUI is a very limited environment, providing a window manager that does not use window decorations and panels for interaction with menus and launching applications.
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