the "ability activates when swapping" thing has to do with the AnyUp/AnyDown option. rdx-actionbars are configured to call the action when a button is pressed down aka OnAnyDown, the default-ui and most other actionbar-mods activate the action when the button is released aka OnAnyUp. depending on your playstyle, using OnAnyDown can decrease the delay between your casts and thus increase your dps. in the actionbar-configuration menu there is a option "use anyup" or something like that in the top section of the menu, if you activate that option the bars will behave like the default ui and wont activate spells if you drag them around.
/e
for demon-form, i just played around a bit with the default-ui and there seems to be no stance-type bar definition for this ?
on my priest, the bar changes when switching to shadow-form, on my druid the bar changes with forms, but for my warlock nothing changes when activating metamorphosis, so to me it looks like there is no specific stance-bar defined by blizzard for demon-form, and if this is true i think there is no way to automaticaly switch the bar with state-definitions in openrdx
