When right-clicking on a heading and selecting “Extract heading” so as to move the whole section into a separate file, heading links relative to the original file should be converted into internal links.
Currently, in the newly created file, links to sections of the original document (that were not moved to the new file) are broken.
A solution would consist in prepending the original file name to Heading links contained in the section, if they refer to a section in the original file (but not if the subsection has been moved to the new file).
Currently, users can take relatively painful extra steps (if they remember to do it!) of converting, say
[[original file name#…]] if the links point to sections that were not moved. Each link must be checked manually: we need to check whether each header link refers to a section that was moved to the new file or not (which can be painful when the copied section is a bit long). That’s a perfect job for a computer!