if you write part of a column name, intellisense gives you a list to chose from, but automatically selects the first row, so you can confirm the choice by pressing TAB. That works in WHERE, ON, GROUP BY, ORDER BY statement, but not in SELECT. I am quite sure that in one old Release this worked. not sure, why it does not anymore.
Right now in SELECT you have to write part of the column name and then use cursor down to select the first item on the list, then press tab.