[Mail] window freeze if you click Trash icon

[diver]

Mail window freeze, to reproduce: *Press alt+n to open new window *click Trash icon to close this new window *click Trash icon to 1st window.

[jackburton]

Mail app lock also by just opening it, and clicking the Trash button. Although in this case the window will close, but the deskbar entry will stay there.

[jackburton]

The problem seems to be a deadlock caused by the BPrivate::BPathMonitor::StopWatching(BMessenger(this, this)) call in MailWindow::QuitRequested().

I followed the code path, and it seems that BPathMonitor ties the PathHandlers to the be_app looper, if available. This isn't so nice, because then, in StopWatching(), it tries to acquire the be_app lock (multiple times, too), which could be already locked in another place (in this case, in BApplication).

We could remove the use of the be_app looper in BPathMonitor (it can also use an internal looper if be_app is not available).

[jackburton]

Fixed in hrev23995.