Automatic hands swapping is annoying, how do I stop it?(SteamVR + VIVE Input Utility)

In short: how do I stop the SteamVR swapping hands at runtime?

The problem comes as I'm using something like

Code (CSharp):

1. ViveInput.GetPressUp(HandRole.RightHand)

And sometimes suddenly SteamVR decides to swap left & right hand role, then the controller button functionality goes onto the other controller: Normally let's say I use the right controller to point to something then pull the trigger to do the job. Now I have to use my right controller to point to the target and pull the left controller trigger.

Did some research and unable to find anything useful, can anyone help me on this? thanks!