Finding any specific post in this forum is very hit or miss. The search tool just doesn't work all that well.
Report an Issue is the established place for reporting possible software bugs.
In this case there are indeed long standing and previously reported differences in the behavior of drop down lists and pop up menus between Mac and Windows platforms. But they are so long standing that they are not even documented in the Known Bugs List as those reports predate the creation of that community supported resource.
I also noted that the drop down list does not activate on Windows by clicking on it with the mouse. It will only activate by tabbing into it.
I think you've got something else involved producing that particular behavior difference. I use windows here and have numerous drop down lists and pop up menus. Clicking a drop down list will deploy it unless the arrow option is specified in the Inspector and when that option is selected, you can only deploy the list by clicking the arrow (and tabbing into the field no longer deploys the list.)
Note: I'm not a Mac user at this time but, another behavior difference others have noted is that you can tab into a pop up menu to deploy it in windows, but not in Macs.