pfSense

Hi! I have an 4 port intel nic, wan on one port, and lan with four vlans on other port. the other two ports aren't used. I was trying to change an assignment for the lan, from igb1 to igb1.2 (vlan 2) and pfSense wouldn't let me do it. Thinking that i had to be something about being connected to that port, and the antílockout rule, I tried to do the same but assigning the lan to igb2, and being connected form there, same change to make lan be vlan 2, but no success. I would hit add and then save, and pfSense wouldn't throw me any error, I just couldn't make it do that.
I entered from the console, typed 1 for assignments, n for not modify/delete any vlans, igb0 for wan, igb1.2 for vlan 2 on igb1, enter to not change anything else, and it worked as expected. I saw something about arp, but i didn't have any problems doing that from the console... wondering why the GUI wouldn't let me do that exact same change, and why it wouldn't show me any errors or clues.