I have a drop down box where the first item is blank indicating they haven't selected anything yet and then it's filled with other choices. There is also an insert button beside the drop down.
The blank item isn't a valid choice to insert so I was going to hide the insert button until a valid choice is selected. To me this seems like a cleaner approach because the user has less to think about. They can only interact with items that are visible to them.
So is this the right think to do, or should the insert button always be visible? And then I would just have a notification indicating they can't insert the item.