Right-click Rescan option in Resource Library doesn't rescan for folders/assets

[Phergus]

Describe the bug
Doing a right-click -> Rescan of a folder in the Resource Library window does not force a rescanof the folder to show newly added folders/files.

To Reproduce
Steps to reproduce the behavior:

1. Open MapTool
2. Select a folder in the library such that folder image assets are displayed in the preview pane.
3. Go to folder with system File Explorer and add a new folder within the selected folder.
4. Return to MapTool and note that it is unaware of new folder.
5. Right-click on folder in Resoure Library tree view and select Rescan.
6. Note MapTool is still unaware of new folder.
7. Repeat steps 2 thru 6 but add a new image in the folder instead of a folder.
8. Note Rescan did not reveal newly added image.

Expected behavior
Expect Rescan to display the current state of the folder with any additions or deletions.

MapTool Info

• Version: 1.5.0+
• Install: Any

Desktop (please complete the following information):

• OS: Windows
• Version: 10

Additional context
See forum discussion.

[melek]

Also occurs on MacOS.