I have set up a related module to connect contacts and accounts. Then I've enabled the display of these related lists within both contacts and accounts. This all works correctly. I am now editing columns for related list displayed within the account. I selected several columns. Out of these, several are displayed correctly. However, two are removed once I complete the edit and save the account layout setup. One of these columns is a string (single line), other is a picklist. I can't figure out a reason why this should be happening. Any suggestions?