From maybe a "logical" approach I should set the timer to "00:00:00". But I could not find a real practical use. The clear button is mainly meant for removing an item (empty text = removal of item at save). The time choosen is not relevant in that case. And even if I only wanted to edit an item by clearing the text first, I am not really helped by a reset to "00:00:00" that much, as I may want to set a time close to the old one.