I'd like to thank Andor Szőke from Graphisoft tech support in Hungary. He persevered with sample files and figured out that the schedule is always placed in the upper left corner of the screen.
I have dual monitors set up separately (not as one). When the I/S window is on my right screen and the main AC window on the left, the placed schedule is in the upper left corner of my right screen, therefore out of view of the left monitor.
Once I have it placed where I want it, selecting and updating it doesn't affect the location of the placed schedule.
Great way to start the new year.
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"