I have an idea for you to perhaps add in as a future update.
I have attached three images that are simply viewed at differing zoom levels. Note that the navigation icon ( or what ever you call the colorful move and rotate tool) appears to be centered on the object/line that is selected. As I zoom in it slowly moves off the screen and at a high zoom level I can not see the tool at all.
Perhaps the tool should be centered on the selected object based on the current zoom level in such a way that I can always see it regardless of the zoom level.
Hope this makes sense. Bret