Focusing local directory tree clears UNC path from local site

[rbbot]

To repeat:

1. Ensure the local directory tree is visible
2. Enter a UNC path into the "local site" text box
3. Press Tab

This gives focus to the local directory control, which changes the local site back to the selected item in the tree clearing the UNC path. This is annoying for both keyboard navigation and for changing to a subfolder of the UNC path.

Ideally, the local directory tree should include the "Network" folder that appears in explorer and the UNC path you entered should appear within it so you can use this control to navigate to subfolders.

If this isn't feasible, merely giving this control focus without changing the selected item shouldn't change the "local site" folder.