I have two comboboxes and two text boxes

the user enters a value in them and selects from the drop down and then
clicks a button which changes the values in autofilter settings of data

What I cant understand is.. once the user selects something from the drop down
and the moves is moved to another cell , the value changes in the dropdown.
however if the mouse is pointed back to the dropdown / text box

the correct value is displayed.

any reason why?