Right mouse button is just one issue. There is many other
issues need to be taken under consideration. One big thing is
dialog layouts. If dialog is so large that part of it is outside of screen
it decreases usability of lot.

Even if you can make technically usable it does not mean
that usability is good. For small screen devices application
with good usability should be usable with finger. As example
acrelling from content pane is much more usable than tiny
scrollbars that require usage of stylus.

Maemo Qt port takes care of most of technical issues like
style and input method but it can't fix bad or unsuitablenUI design.

I strongly recommend that everyone that ports application to maemo
pays some amount of attention to usability and is just not
trying to make quick and ugly port.