Sometimes terminal control doesn't get any input

[Ilya Biryukov]

Whack Whack terminal version: 1.0.14

Sometimes, maybe one time in 50, Whack Whack terminal doesn't get any user input and ignores all keystrokes though the control looks focused and the cursor is blinking. Clicking around in VS doesn't fix that, the only way to fix I found is to do Ctrl + Tab, switch active tool windows, and then switch back to the terminal.

Debugging the terminal code in this weird state shows that:

1. Focus events seems to fire as expected.
2. TermView.termData events do not fire.
3. xterm AccessibilityManager._onChar do not fire.
4. BetterBrowser.Browser_PreviewKeyDown do not fire.