OO.ui.mixin.DraggableElement has two ways to set its draggable state - via the constructor config, or via the toggleDraggable method.
There is a list of problems in this redundant implementation.
Via the constructor:
- the class oo-ui-draggableElement-undraggable, indicating that the object is not supporting dragging at the moment, is not added (compare toggleDraggable method)
- the draggable attr does not get set based on the object property but is always true (might not have negative effect, but is weird)
Via the toggleDraggable method:
- large parts of the method are only run if a change to the object property is performed. That means that calling toggleDraggable(false); stays without effect after constructing the object with config { draggable: false } and leaves the object in an undesired state (while specifying the opposite twice)
Might be what T129184 tried to describe.