This is an area that I seem to be having the most trouble with as of late. I have a 14 min video and I am almost done with editing when I decide to add a music track or add a few clips. When I do add it instead of just pasting it to the time line it inserts it but moves the whole, or worse, sections of clips up the time line. When I go to trim the music track, it again edits my video. Very frustrating. I select, hit U, then go back to editing just the music clip but it almost always changes the video too. I discovered by accident that I can paste something into the time line by quickly hitting my right mouse button and it will actually paste in that spot without messing up what is their already. Can someone set me straight on groups. Thanks.