make diff window close with ctrl-w / ctrl-f4
At least on WIn10 I can't close diff tabs (ctrl-d) using the standard keyboard shortcuts.
Plastic for Windows: The diff tab couldn’t be closed using the default shortcuts Ctrl+W/Ctrl+F4. Now it’s fixed.
Plastic for Windows: Using the tab key to navigate controls did not work in the diff viewer when it was embedded in the pending changes view. Now it’s fixed.