MacOS version incorrectly behaves as if CTRL is pressed

[GMinchin]

Sometimes the Mac OS version behaves as if I'm pressing CTRL when I'm not. e.g. Mouse-clicking a component toggles its selection rather than making it the only selected item. Or I just noticed that pressing "2" toggled the Design Manager pane (as you'd expect from ctrl-2) rather than selecting layer 2.

It happened in version 4.x and still happens in 5.0, and it has happened on several versions of Mac OS (currently Sonoma, but on all previous versions too).

I particularly notice it in the Schematic and PCB editors. I assume it also happens in Component and Pattern editors, but I spend less time using them so it's not as apparent.

It only happens when I've been using another application, then switch the focus to DipTrace. e.g. I'm reading data sheets in Safari, for instance, then switch to a DipTrace window which was already running. Most of the time it doesn't happen and I don't know a sequence that makes it happen every time. I've just tried a test, switching focus between Safari and DipTrace using the mouse and/or using CMD-TAB, and it worked correctly every time. I can't pinpoint what triggers the error. My impression is that it's random, but that's probably not true.

The solution is always simple - tap and release either the CTRL or CMD keys and then everything is good until DipTrace loses focus again. It never happens while DipTrace keeps the focus.

[Alex]

Thank you for the extensive research, this will help us for debugging Mac version in future.