When editing a section, the section itself will be saved, but another version of it may be displayed in your Content Library instead.
Here's how you can save another version of a section from your proposal to the Content Library:
Go to the proposal editor and find the section you want to save
At the top of the first page, click the "Last Edited by" wording, next to the section title to pull up your Revision History.
The top most version is your default.
Below your default will be all the versions of that section edited in that proposal or template.
The Revision History holds a version for each proposal/template that section is used in. So if your section is being used in 1 template and 2 proposals, you will see 3 versions in your Revision History list.
Push & Pull
Edit in Library - will open that section in your content library where you can edit the default version. Remember: It may look different because when editing sections in the content library the styles are defined by which template you've set as your default template
You can click here to find out more about how this works.