Steps:
- In a plugin or the console, do:
other_window.focus_view(other_window.views()[0])
- other_window will be apparently focused (the current view will be defocused), but it will not be in front, and for the user it appears that nothing has happened.
- Alt-tab to another application.
- Alt-tab back to Sublime Text.
- oher_window will now be in front, and will have focus.
This bug prevents me from writing a particular plugin.