void CreateKeysUnderMouse ( const FVector2D & MousePosition, const [FGeometry](API\Runtime\SlateCore\Layout\FGeometry) & AllottedGeometry, const [TSet](API\Runtime\Core\Containers\TSet)< FSequencerSelectedKey > & InPressedKeys, [TArray](API\Runtime\Core\Containers\TArray)< FSequencerSelectedKey > & OutKeys )