Mouse clicks aren't picked up when framerate is low

From the [original project](https://github.com/cebix/macemu)'s [`BasiliskII/src/MacOSX/ToDo.html`](https://github.com/cebix/macemu/blob/0a7fe2eaf8e88a458836c3ec1f382906b253d85a/BasiliskII/src/MacOSX/ToDo.html):

> In window mode, if the framerate is low (e.g. if you leave it at the default of 10fps) or if the emulated screen is too large, really fast mouse clicks are sometimes not picked up by the Emulator. For now, click more slowly.

No further information is available; it's also possible that this issue has been addressed in the time since that 2007-07-14 revision.