I was having the same trouble, and not just with Far, Far Away, but with many transitions and titles. Very obvious adjustments we'd like to make are not available. I have found a cumbersome workaround, perhaps someone else has a better one or perhaps Apple will wake up and make their app more "intuitive."
Apparently, iMovie 10.0.7, which I am using, only wants to allow "clips", meaning real video, to be manipulated. So I took the title out of iMovie into Quicktime and reimported it so it became a video clip.
Details:
From your event
Start a new movie, and pull a title you want into it (just the title will speed up your workflow - no other clips on this new movie)
Add text as needed
"Share" the little "Title" movie as a file to your desktop or someplace easy-call it title or something you'll remember-I actually set up a folder to use and put all these little things in there until I am done making the movie, just in case I need them again
Mine all come out at mp4. Don't know if that is universal.
Open Quicktime, navigate to your little "Title.mp4" and open it in Quicktime
You can trim it in Quicktime, but I don't
I then export "Title" to my same folder, it seems to always go out as a .mov file, again, don't know if that is universal. as a .mov file (since iMovie will not import the same thing it just exported, we know it is a complicated thing computer-wise, but it would certainly be a boon for the user-go figure)
Import the "Title.mov" file to your event in iMovie
Drag it where you want the title
You can then slow it down or whatever, and trim off the end, making some kind of transition if you'd like to the next clip.
I'd really like to be able to do some more modification at that point, and the downside is you cannot modify the titles after the share from iMovie, but if you do each title separately, it doesn't take long to redo it if you don't like it. Not perfect, but it worked for my purposes. Hope it helps.
It is the dumbest thing, and we should not have to do it, but I am not a professional and making only occasional movies, and had hoped iMovie would be easy. No such luck.