from JavaTM ME Developer's Library 3.0, Touch UI support - Displayables and Commands, Section Canvas:
"Touch down and hold opens a pop-up menu containing item specific commands, if available (corresponding to a context specific options menu in a non-touch device) except in full screen mode Canvas"
My initial reaction is to expect the opposite logic for the pop-up menu...
a) in full screen mode there are no soft keys, so having access to pop-up menu option is very useful
b) in normal screen mode there are soft keys, so pop-menu (as already provided on left soft key...) seems redundant
Maybe having api control of this pop-up menu would be a better solution?