Why do I get unexpected results when using Igor Pro 7 with Spaces on Macintosh OS X?

Using Macintosh Spaces with Igor requires care. The common use case for Spaces and Igor is to put all Igor windows into one Space so that Igor windows can be hidden or shown all at once. That use works fine.

Problems can arise if you have Igor windows existing in different Spaces. In particular, if you have two monitors, and you have turned on the Mission Control setting "Displays have separate Spaces", you can see one possible problem with this sequence:

Make two graphs.
Drag one graph to your second monitor, which puts it into a different Space.
With that graph as the active window, pull down the Graph menu on that monitor. Select Packages->Make Traces Different.

You will see the Make Traces Different control panel appear first on your main monitor, then move to the second monitor. Appearing on the main monitor causes that Space on that monitor to become active, and the first graph becomes the active window at the same time. Now elements of the control panel appear in the graph and run-time errors occur. The control panel is a mess.

We don't have a good solution to tracking changes in window activation when we don't expect it. So our recommendations are:

1. We don't recommend the "Displays have separate Spaces" setting.
2. But if you're careful, you can use that setting, but you need to keep all of Igor's windows in one Space.
3. Those with just one monitor won't have the "Displays have separate Spaces" setting, but you might still have multiple Spaces on your one monitor. The recommendation still stands: make sure Igor windows are all in one Space.