Media after relinkin in timeline offline

Hello,
I guess when it comes down to relinking media in FCPX it's still a big pain in the ****. I relinked an audio clip which i already had in the timeline and now the clip is offline. match frame doesn't work although the clip can be found in my project.
I work with 10.1.1. I didn't copy any media to the library. I also had the same problem with projects when i copied the media to the library.
Often FCPX won't allow me to relink media to files which are different to the original. Like an audio track which has the same name but a different length.

i appreciate any kind of help.

cheers