There is some confusion here. Most of the object in FC has a 'Placement' property. Its value type in Python is 'App.Placement' (note the dot instead of double colon). The dragger manipulates the Placement property without recomputing, so you see the movement in realtime. But once you click OK, it will trigger a recompute, which is when the expression engine kicks in and overrides the placement.Zolko wrote: ↑Tue Feb 19, 2019 11:03 pmWhat I understand from this is that this dragger temporarily disables the App::Placement of any object, and replaces it with its own Placement. And when it's done, it stores the value in the App::Placement of the object ... except that the Expression Engine doesn't allow the overwrite.
Now, rather confusingly, there is an object with type 'App::Placement'. And last time you said you want to add custom property to it, I provided the 'App::PlacementPython'. Is this the object you are using for your constraint? This object also has a property 'Placement', and it supports the dragger as well. So if I understand correctly, your problem can be solved by NOT moving your part object with the dragger, but the 'App::Placement' constraint object directly, with the right click and transform action.
If there is any other confusion, it would be better for you to provide a file and tell me exactly which object you want to move.