>>>Yup, popup's the word which I couldn't remember, personal pref... impediment. I never understood why they had separate code and vocabulary for menus, to apply one set for the vertical case, another for the horizontal case. They're the same otherwise.
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>>[shrug] perhaps different nomenclature appeared due to historical reason? If not mistaken, (vertical) popups can appear outside of the context of the (horizontal) menu bar. Also, if I'm not mistaken (vertical) popup can be used as data source for lists, but (horizontal) menu bar can't.
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>I wouldn't be surprised if you could do that with a horizontal one as well. You have a set of clickable labels, basically, with their surrounding rectangle, laid out in a line. Whether the line is horizontal or vertical affects only their layout, not the functionality. So the decision to have AT clause in activate popup but not in activate menu is actually quite arbitrary. The code inside is the same.
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>Or, if it is not the same, then I consider it a serious consequence of the western inductive method of learning (specially sciences). Someone failed to notice the identical behavior and wrote code twice.

Obviously the horizontal one is designed to stuck on a window (...), while to vertical one is designed to float and be visible only temporary. For the designers that time it was a huge enough difference?