You can download the Tcl/Tk source text for the example from http://www.hwaci.com/sw/tk/tree.tcl. The source text is about 260 lines of pure Tcl/Tk code (not counting the 50 lines or so of code needed to implement the demo.) The widget itself will run on Tk4.1 or later. The demo uses the "-data" option to the photo image, so it requires Tk8.0 or later. The only documentation currently available is the source code itself. A document describing the operation of the widget is forthcoming. More Tcl/Tk Widgets
You can download the Tcl/Tk source text for the example from http://www.hwaci.com/sw/tk/tree.tcl. The source text is about 260 lines of pure Tcl/Tk code (not counting the 50 lines or so of code needed to implement the demo.) The widget itself will run on Tk4.1 or later. The demo uses the "-data" option to the photo image, so it requires Tk8.0 or later.
The only documentation currently available is the source code itself. A document describing the operation of the widget is forthcoming.
More Tcl/Tk Widgets