itunes playlist songs greyed out

hoping some one can help.....I recently needed to create a couple of new playlists to host a kids disco. I popped the songs in order and selected them to cross fade to keep the music running, but when I pressed play only 5 songs would cycle through, they appeared in black type face all the others were grey. If I manually clicked on the grey song it would play, but otherwise it would jump to the black songs.

Any suggestions on how I can fix this?