Slate focus mouse and unfocus

Hello, I am currently working on an inventory system where pressing I opens the inventory.

My player controller looks something like this



void ATestHUD::OpenInventory()
{
	if (Viewport && bIsInventoryOpen == false)
	{
		SAssignNew(MainInventoryUI, SInventoryWidget)
			.InvStorage(StoragePtr);
		Viewport->AddViewportWidgetContent(
			SNew(SWeakWidget).PossiblyNullContent(MainInventoryUI.ToSharedRef())
			);

		SAssignNew(CursorItemUI, SCursorItemWidget)
			.InvStorage((StoragePtr));
		Viewport->AddViewportWidgetContent(
			SNew(SWeakWidget).PossiblyNullContent(CursorItemUI.ToSharedRef())
			);

		CursorItemUI.Get()->SetVisibility(EVisibility::HitTestInvisible);

		bIsInventoryOpen = true;
	}
}

void ATestHUD::CloseInventory()
{
	if (bIsInventoryOpen == true)
	{
		Viewport->RemoveAllViewportWidgets();
		bIsInventoryOpen = false;
	}
}

It works fine but at the start my mouse doesn’t focus to the slate view port. I have to click once to get it focused.
A lot of things have changed in 4.6 and old things in the answerhub don’t seem to work.

How do I focus to my slate and change the focus work? Something like SetUserFocus but I am not sure how to call it.


FSlateApplication::Get().SetUserFocus(1, MainInventoryUI);

This is such a simple thing basically each and every menu, inventory system uses it but why isn’t it documented at all?