impossible to "half open" a drawer programmatically

I need the side drawers to be opened by an external handle, but besides just opening/closing by click (supported API in Drawer) i also need to open the drawer by dragging the handle.
This worked well in Qt 5.7 in which my mouse area could just set the position property of the Drawer, achieving an external drag handle that could control the Drawer position.

However, since 5.8.0 Alpha (and still in 5.8 branch), this doesn't work anymore, as setting the position property of a Drawer that's not visible, doesn't make it visible (unlike 5.7 behavior) and setting it visible beforehand kinda works, but has problems as well, since it wants to run the enter transition animation on the position property itself (from 0 to 1)
making impossible/flickery to manually control the position property.

it should either keep the 5.7 behavior (behavior changes aren't good anyways) or there should be a way to control the transition, to disable it completely and go completely on manual control (the enabled property of the Transition seems to be completely ignored at the moment, I would expect the animation to not hapopen at all if it's false)