spurious content changed event (1.2.0 regression)

After commit 4efd886c window title changes without content changes in inactive tab.

I think the issue is that the content changed event gets queued up before switching to other tab and the tab changing itself does not clears the queue.

Can be easily reproduced by opening multiple tabs in one window with hotkey Ctrl+Shift+T by default), some tabs will change title color without content changes.