Child elements within a page are typically opened for shallow editing on the Page tab. However, if a page contains a lot of children, auto-opening them all can result in a very large, long page.
Therefore, the system imposes a limit, as set by the site/subsite variable PAGETAB-COMPONENT-LIMIT. The default limit is 15.
If there are fewer children than the limit, then the subelements are auto-opened for appropriate shallow editing. If there are more children than the limit, then the subelements are not opened, and only a single access line is created for each child. In this case, the user must click into the child element to mini-edit it.
NOTE that once the user clicks into the element, it is opened for shallow editing within the Page tab of the parent.