That pencil icon is the "record is dirty" icon. In other words, changes have not yet been saved to the table, you can still press escape or Me.Undo and go back to how the record was when you started. I'm guessing you're just saving the record when that happens, and that could be done with a number of VBA codes.

I personally use Me.Refresh or If Me.Dirty=True Then Me.Dirty=False but there are other ways like docmd.save

What Adam Said. The pencil is to tell you that the record is Dirty, therefore not, it isn't saved. It isn't designed to be clicked.
When your user is clicking the pencil icon, they are essentially leaving the record and thus its saving (or committing) the record to disk.

If you aren't familier with VBA, the topic is covered in Beginner Level 1 (Specifically Parts 6 and 10).
If you are familiar with VBA, you can use the On Dirty Event (To capture AS SOON AS the record goes dirty) or the After Update Event (After the record has been edited and committed to disk). Then just use the commands Adam shows above