Significant memory leak in the UKS Dialog

[FutureAIGuru]

Describe the bug
Memory leak in UKS dialog. Other dialogs have some leaks too.

Application: Brain Simulator

Module/Network: (if your network, please attach XML file)
UKS

To Reproduce
Steps to reproduce the behavior:

1. Open the SimVision network
2. Click on the ">" to turn right (the leak doesn't start before then
3. Notice that memory usage continues to creep up.
4. If the UKS content is large, the system will exceed several Gig in a few minutes.
   For some reason, the TreeView doesn't release it memory. This has also be observed in other dialogs where the canvas does not release the memory of the children but the amount of memory is smaller for these objects so the leak is slower. This points to something generic in the base dialog.

Expected behavior
Memory shouldn't leak

Add any other context about the problem here.