HideOnFocusLost causes problems with keyboard focus

[dfyx]

When I set HideOnFocusLost to true and click outside the terminal, it disappears as expected but keeps the keyboard focus. This is easiest to see when clicking a text box in another program (for example the GitHub issue form) and starting to type. The typed text doesn't appear in the text box but as soon as you re-open the terminal you see your text there.

[flyingpie]

@dfyx Thank you for reporting this! What an interesting bug indeed. I'll investigate this and see if it can be fixed for the next release.