Unable to view repository settings?

I open a repository view, and when I select "Repository settings" from the menu the window is shaded (as though a dialog is going to appear) but no dialog appears.

I can still access the Sourcetree window (which lists the various repositories) but the actual repository view is inaccessible.  I can't close it, I can't quit, in fact they only way to get out is to force-quit sourcetree and restart.  Then I can view and commit my changes again.

This came about because my github access token was expiring and I needed to create a new one.  Now I can't load this new access token into the repository.

PS Updated to the latest version - it is still happening.