selecting an item in combobox, the item does not get selected

I am getting close to finishing the drop down menu capability when filling in column L in tab Transactions. However, there is a snag. When I enter part of account say "fin" (the important part here is that the part of the word should not be the beginning of the account name) - then I select an account from the menu - but it does not stay in the cell if the part of the name is the beginning of the account name - all is fine. How I can have this fixed?