Not as far as I know. There are no actions/events to move the cursor to an object.
You could use two list boxes and show the second one only when a selection has been made in the first one and also hide the first list box (or disable it by showing a semi-transparent text box on top of it). You can use the Conditional option on the Layout tab to enter an expression that evaluates the number of selections in the first field; something like =if(getselectedcount(KeyPart1)=1,1,0)
Withthis solution, theuserwould have toalsouse the mouseto click the searchiconin the list box. Sono realbenefit for the user. Is it possibletocustomize thelist boxsoonlythe search option is available?