Here is a new tmap.b with the memory leak removed. I just needed to call Tk cmd delete all on the canvas to remove all the old rectangles.
And finally a screenshot of tmap using output from du -a / on the root of the Inferno distribution. You can see a file and it's path highlighted in red.
I've played about with the coloring a bit, but haven't found anything I really liked. The current scheme is for colors to represent depth. It goes from dark blue to light blue, through greens and yellows and ends on red for the deepest nodes.