The Accord Vikrell Seated Shower has a gap between the end of the seat and the inside threshold of approximately 1 inch. A shower curtain could fit in this gap. If the shower curtain runs longer, it could be pinched between the seat and the threshold.
During testing, it was discovered that a longer, pinched shower curtain may be better. If the shower curtain is not long enough, during showering, the water may run down the front angled side of the seat and kick the shower curtain outward causing water to exit the shower and get on the floor. If it is pinched, the shower curtain will stay in place and prevent water from exiting the shower.