Thanks for the reply, I understand your point, this should absolutely not be built in to juce if it were not a windows-level feature! But it seems to me that it is:
This happens on both my touch-screen computers, I've now also tested on my Lenovo Yoga 14, running windows 8 (the wacom machine runs 10). The Lenovo is your average cheapo windows touch-screen, and not at all a specific device like the wacom screen.
When I press and hold with the finger in my Juce program, the transparent rectange indicating a long press appears, meaning it is a windows/driver-level functionality. And, after seeing that rectangle indicating the long press appearing, one would assume as a user, that the right-click that corresponds would follow.
In all software, (e.g. windows explorer, firefox, Notepad++, WinRAR, etc ), this work: after the rectangle around the finger appears, indicating a long-press, right-click is triggered.
If it were as you say, that it is up to the app developer to support this or not, then the rectangle indicating long-press shouldn't be appearing either, no? At the moment it appears everywhere, JUCE included, but then in JUCE the expected behaviour, the right-click, fails to happen.
If all other software I've tested behaves this way, then, I would say that JUCE not doing so is inconsistent, and, may I insist, somewhere a right-click event from windows gets lost...