Inline Cell Group Openers
Cell groups have been a hallmark of notebooks since Version 1. Closed cell groups can make it very easy to understand the outline of a given notebook. But until now, they have required carefully decoding the cell bracket hierarchy on the right side of the screen to know that a closed cell group exists that can be opened.
A typical notebook with closed cell groups.
Mousing over the inline opener reveals it is a button that can be clicked.
The opened group reveals some subgroups that have already been completed and some subheadings that have not been filled in yet. Identifying the empty subgroups is now much easier with the absence of the opener.