:vimgrep can list search result in the Quickfix window.
:cn can jump to next matching and NORMAL window is also updated.
If switch to NORMAL window and n, it will jump to next matching place, but Quickfix windows is unchanged.
Can we make NORMAL and Quickfix window fully synchronized?
:cnseveral times and in NORMAL window you navigate to the first match, then:cncan't bring you to the second match. Basically we can't synchronise from NORMAL to Quickfix window. – Fisher Jan 18 '18 at 14:27