Repro steps:
1. Create a new VFX
2. Add it to the scene so it's visibly playing
3. Add any property to blackboard (i.e. Vector3)
4. Click on the property, hold down the left button, quickly move the mouse into the graph without releasing the button and stop
5. The mouse cursor shows that a drop is not possible.

Expected result:
To allow properties to be released.

Notes:
- This only happens in the mouse is moved quickly from blackboard directly and is kept still once it stops.
- Moving the mouse fixed the issue and the effect can be successfully dropped.
- The effect has to be in the scene and previewing for this to repro.
- Issue brought up on the forums.