Mouse position not updating when holding left mouse button?

Hi ,

I have created an in-game level editor.
This is happening when in-game using PIE or Standalone. While holding down the left mouse button the mouse cursor disappears and locks into position. This is making it difficult for me to select my custom actors in the in-game level and move them around with the left mouse cursor. I am able to bind the same movement functionality to another key on the keyboard and my logic works perfectly, only with the Left Mouse button does the cursor seem to disappear and lock, unable to move.

The logic should be very simple as it works with any other key, apart from when holding down the left mouse button:

PC->DeprojectScreenPositionToWorld(GetMousePos.X, GetMousePos.Y, WorldLoc, WorldDir);
FVector NewBuildPosition = WorldLoc + WorldDir * ActorDistance;
ManipActor()->SetActorLocation(NewBuildPosition);

I’ve also tried a Deproject method from my HUD class directly from the Canvas (which was my original method before using the above) but still no luck which is making me feel as though something has changed within the Engine concerning this since 4.9.

Cheers,
Jon