No trick..........just slow & steady. Prise it open with a screwdriver, but don't hash it. It's spring steel, so if you overstress it it'll either break or permanently deform. Open it just enough to clear the detent & lever it free
Tnx... I didn't know if you had to try and nip them to release :augie Until you do it once, like I have had to do to get at the hot/cold cable control, then you know how to remove stuff and how to access screws.