Multiclip: Changed angle now now normal clip

Hi everybody

I changed the angle in the viewer, while the video was not playing to make not a cut but simply change the angle of the already cut clip. I know I should I have done this with the options-menu of that clip changing the active camera. Unfortunately, this clip became a normal clip: I don't see anymore two cameras as usual in the viewer, only the same picture as in the canvas and I cannot select reduce multiclip. It is like a normal clip.
I cannot simply undo, because I made already other changes. What can I do to go back to the multiclip?
I noticed also that in the timeline I have for the multiclip always a green line (Preview), but for this normal clip there is no color label.
This happened when I did already the multiclip cut and did some additional editing afterwards. Another strange thing was that in the timeline only the first cut was actually done. The other cuts produced only a marker, but when I stopped playing this markers got lost. This was, as said before, after the main cut.
It seems that when you cut a multiclip in sequence, than no problems occur. But when you cut in between some clips separately FCP gets crazy.