how I keep my shower curtain from gapping open at the end
I installed a Command hook inside the shower (spaced it the same distance as the space between the shower-curtain holes).
Then I took off the last shower-curtain hook, and I hook the shower curtain over the stick-on hook.
This makes the shower curtain turn the corner and STAY inside the enclosure.
I also push the last shower-curtain hook up against the wall.