How to prevent multiple arrows from showing on the Expert Advisor

I just need one arrow to show at the initial entry point. Instead, every time my entry requirement is met, I get a new arrow.

Make sure to review training lesson 4 on latches:

buy:= c> mov(c,10,e);

sell:= c< mov(c,10,e);

buy and barssince(ref(buy, -1)) > barssince(ref(sell, -1))