Detecting the active monitor under Mavericks and Yosemite...

[Paul Dupuis]

Starting with OSX 10.9 and 10.10, Apple introduced changes to how
multiple monitors are handled. The menubar appears on all monitors and
when you drag a window from one monitor to another the menubar for the
application that window belongs to becomes active on the target monitor.

Question: Does anyone know if there is a way to detect which monitor has
the active menubar under 10.9 and up? I don't see any obvious dictionary
entries for detecting this in LC 6.7 or 7.0, but maybe there is a
non-obvious way.

I believe that from an UI perspective, an application should open new
windows on the monitor which has the active menu bar for the
application, but that requires the ability to tell which monitor has the
currently active menubar.