If we could click and activate to open aircraft doors, windows etc. then it makes it difficult to target things.
Also, and mainly where I notice the issue, is that I use the Campout utility from P42 - this together with your fpv were made for each other, I'd recommend you try it out if you haven't already.
It works fine from fpv but in order to move the mouse up to the toolbar you end up looking straight up. Similarly, when then trying to place the campsite objects around your plane using the mouse your view is moving around correspondingly rather than being able to look where you are building your camp.
Hey Captains, while in fpv mode, you are not inside the cockpit, what mouse interactions are you looking to use?