Hi there. I'm new to FCPX and I found it very strange that FCPX doesn't have a "Go to Beginning" [STOP] button under the viewer. I tried to look for it under the Command Editor and it was assigned to a key that doesn't exist on my keyboard. So this is what I did for an alternative, I assigned "Go to Beginning" to the "Return" key. This change has been really helpful because now I can jump to the beginning of my storyline and preview it to see how it all flows. If you would like to do this but don't know how to do it, here's how:
1. With FCPX open, press option command K
2. In the search bar (top right of the HUD), type "Go to Beginning"
3. If you look at the Command List, you can see the "Go to Beginning" command (it is in purple).
4. Drag this Command to the Return key (or a different key if you want).
5. Close the HUD and save changes.
Test to see if it works! Click anywhere on the storyline and then click your assigned key (in my case, return).
8-Core 3.0 Intel Mac Pro, Dual 2 gig G5, AJA Kona SD, AJA Kona 2, Huge Systems Array UL3D, AJA Io HD, 17" MBP, Matrox MXO2 with MAX - Cinema Displays I have a 22" that I paid 4k for still working. G4 with Kona SD card, and SCSI card.