Thanks for the details on workarounds. We have submitted the issue to the vendor of our tree component and the makers of WindowBlinds. The tree vendor won't investigate because they (understandably) don't explicitly support third-party Windows extensions such as WindowBlinds.
The only way this will get fixed is if the WindowBlinds folks make their product more compatible with plain vanilla Windows so that the tree component works properly under WindowBlinds. We haven't heard much from them on the issue yet. Their contact info is
support@stardock.com (reference Ticket ID AKC-878389, SftTree/DLL WindowBlinds incompatibility).