I've been fighting a small leak in the shower when in use. Water is leaking out from BEHIND the front lip of the shower at the roll curtain base. It runs down the front of the shower base and pools on the floor. So today I THINK I solved it. Nearest I can tell water is running around the "joint" between the surround and the base. It then must build up high enough to get behind the surround at the base at the shower curtain framing. The bottom most screw must be allowing water to get behind the shower base lip and run out in front. Lost yet? See photos. So I pulled the screw and caulked the screw hole before reinstalling the screw. Also added a little sealant at the bottom of the surround for an inch to direct water back into the shower base.
The bottom of the surround has a lip that angles back to the wall and since my surround has a small bow to it, any water that may get behind it, will run out.
Time will tell as soon as it dries. Only other thing I can think of is that there is a screw in the bottom of the roll curtain. Can't believe they would do that, but I've seen worse.