Status Chart add dot

Is there a way to add a dot on the status chart if a block has some kind of data associated with it?

We have operating double click a block of time on the status chart and then they can enter comments. The operators have requested a say of seeing if a block of time already has a comment entered against it. one suggestion was to a have a dot display at the beginning of the block of time to signify that a comment has already been entered.

Thank you,