When you apply any of our modules to a page it can cause an overflow if there is a lot of content in the module displayed.
A good example is the TOC, Table of Content module. This module, depending on how many pages, headings you have in the manual, will populate a lot of data causing a red line to appear on the page indicating overflow. How to control the overflow and cut it to continue on to the next page, is by adjusting the Number of lines to show.
Number of lines to show
Adjust the number of lines that you would like to be displayed in the ToC.
Note: this is also the way to control your overflow. If you have content in your ToC that caused overflow you can reduce the number of lines to show and then apply the module again on the next page and it will continue automatically.
The setting "Number of lines to show" in the module is appearing in many of the other modules as well and is to be used the same as the example above to control overflow.