How do I change the start/end time of a clip in Final Cut Pro X without changing the duration?
With the Open Clip option, the reason that it's not taking any of the changes is because the Arrow tool is selected. Hit the tool icon and choose Position and it'll start taking your changes.



The Clip Trimmer feature in iMovie does not seem to have an equivalent in Final Cut Pro.

This is unfortunate, because one of the other really cool features of the clip trimmer, is that it shows you the start/end frame as you drag the clip which saves you time.