Bug: Wrong Mouse Position during Drag&Drop

Development Programming & Scripting
1

I’m fighting hard to implement some Drag&Drop. I noticed that reading the mouse position during a Drag (at least in OnDrop()) gives 0,0 or -1,-1 depending on what function you use.
I use these functions:

FIntPoint Common::GetMousePos()
{
	if (!world) return FIntPoint(0, 0); 

	FIntPoint mc;
	FViewport* v = CastChecked<ULocalPlayer>(world->GetFirstPlayerController()->Player)->ViewportClient->Viewport; //

	v->GetMousePos(mc); // this gives -1,-1
	return mc; 
}

and:

FIntPoint Common::MouseToScreenPos()
{
	if (!world) return FIntPoint(0, 0);

	float mx, my; 
	mx=my= 0.0f;

	APlayerController* pc = world->GetFirstPlayerController(); 

	if (pc && pc->GetMousePosition(mx, my)) //GetMousePosition() returns false
	{
		float Scale = UWidgetLayoutLibrary::GetViewportScale(pc);
		mx = mx / Scale;
		my = my / Scale;

	}


	FIntPoint mc(mx, my); 
	return mc; 

}

Is this a bug or design? Thanks so far.

2

I have the same problem in 4.13. How did you solve it?

3

I switched to Unity (for this project).