I have changed this to LGPL. No problem since I do not care and the least license I've found here:
is LGPL. So there you go.
I am planning to replace both controls (TreeView and pop-down autocomplete textbox with different controls and when I do this we can have this for even less (but this may take a few weeks in the making..)
Thanks for your hint please give me your feedback if you find something noteworthy...