So i have a records which have a drop down menu. the menu consists of 3 different options to choose from. the user can type anything into the field if they wish. what i would like is to restrict the amount of different items they can type. so in my case the three options in the drop down list are: "block, all fade, assert" they are allowed to enter one other custom value but only one. is there a way to make it so that this field can only accept 4 different values? they are allowed to have many records with the same value but they can only use 4 different values.
if this makes any sense i would be much appreciated if anyone could help. thank you