Both Print dialog and Export in PDF dialog allow to select which page to print/export. When you want to limit to certain sections of the document, one needs to identify on which page they are. Proposal is to allow the user to select sections/part of the tree of headings and the software will determine which pages to print/export. It can be done by having the option to select headings or by having a window to select the headings and then it populates the Page field to print/export. When reviewing a document (in paper) or sharing it, such function would be very handy.