I just ran into this problem and took a look here. I’m not very computer savvy and my F7 and F8 keys are doing desktop stuff. Hmm, I just thought maybe I could go to my Final Cut preferences and have a look, but anyway, for now, that didn’t work but I did capture a screenshot. Now I have no idea how to post it, but I’ll try to figure that out right now.
Okay, after a few seconds of consideration, I won’t figure that out now, and I’ll go try to check my Final Cut short cut keys or mac preferences or something. I’m new to Final Cut, and the source patch things disappearing is a real ball buster. It happened when I was trying to find the match frame from a bunch of video only that had been edited and bring in the audio for them. I was marking the clips in the timeline, pressing F to match frame, and making the overwrite and then I changed all the audible levels of the now linked sound clips- but somewhere along the way I might have tried removing marks from the timeline with Option-X, but could have hit Control-X or something; anyway, when I looked up they were gone – and with them, my hopes and dreams of editing.
;o)