That’s an unfortunate side effect of setting the mouse mode in GTA V to “Windows” instead of “Raw Input”. Changing it back to “Raw Input” should get rid of it.
Alternatively you can still use the menu with the cursor keys, but that’s also not ideal, as you have to hold your head completely still.
I’ll look into a way of circumventing this, but can’t promise anything yet.
For now “Raw Input” is the way to go for comfortable vorpX menu usage.