[Dev] Minor breaking change

[Bryan Stearns]

Aparna (and everyone else),

I'm about to check in a bunch of bug fixes, but they introduce a new bug 
that I haven't been able to fix. In the interest of getting the other 
fixes in place for the 0.5.03 milestone, I'm checking in anyway.

The new problem happens on Windows only: If you switch to another 
application while you're editing the headline or location of an item in 
the detail view, Chandler will crash (and quit immediately, possibly 
leaving your repository in an untrustworthy state) when you switch back. 
To avoid this problem, click on the notes field before switching out.

I hope to have a fix soon; in the meantime, I've filed a bug for this 
problem: it's #3176.

...Bryan