Display toast notification when toggling AVIM if toolbar button is hidden

[1ec5]

If AVIM’s toolbar button is hidden or in the application menu, toggling AVIM via the double Ctrl shortcut has no visible effect. There’s an audio cue, but it’s very common to have the volume turned down or muted.

In this case, AVIM should use nsIAlertsService to display a toast notification appropriate to the user’s operating system. Hopefully that won’t be too distracting. A subtler way to communicate the state change would be to temporarily change the status bar text.

[1ec5]

Some of AVIM’s users typically write in other languages and only pull out AVIM once in awhile. These users often disable AVIM’s toolbar button or hide it in the menu. They would be well served by a notification of some sort. As it is, they get surprised when they accidentally double-Ctrl and weird things start happening to their input.

System-standard toast notifications are too distracting; they’re huge and last too long. Instead, a doorhanger will appear for 2 seconds, pointing to the application menu, displaying the contents of the hidden toolbar button. It’ll be a bit more translucent than most doorhangers and won’t receive focus automatically.

The doorhanger may satisfy some users who want to know when AVIM is enabled but don’t want it taking up space in the toolbar. Other users, however, may have disabled the toolbar button because they really don’t want to see AVIM at all. I think this doorhanger is still useful for them, because otherwise they have no way of knowing that their Rs aren’t going to turn into hooks.