Notepad++ ignoring search results on same line

To answer the question there is not that functionality, but it would be a good idea. Feature requests for Notepad++ can be submitted through IdeaTorrent.

A work around is to use a regular expression that swallows the rest of the line. For example is you want to find lines containing abc you can search for '.*abc.*' under regular expressions and that will find every line with abc but will only list it once.