You've placed some text into your Timeline and need to drag it out (yes, you can COMMAND + J it instead, I know) but for some reason you can't drag it any longer. Cthulhu has decided to make your afternoon a little more hassleful but you can fight back.
You need the lower text element to be as long as the other but it won't drag (extend) any further. Here's why:
If you double click the text element in the Timeline to load it into the Viewer (that's what those perfs are telling you and if you don't know what a perf is I'll cry and feel even older, thanks) you'll see that the portion of the text you've placed into the Timeline, as demarcated by the In and Out points is near the end of the text element. You can't drag it past the "end" of the text element. The solution? Move the In and Out points of the text element.
This is what it'll look like after you move the In and Out points of the text element further back. Since text elements don't change (default ones anyway) the text on screen will look the same. But how can you move both simultaneously?
Hold down SHIFT and Click and Drag either the In or Out point and you'll be able to slide both, simultaneously left (or right if for some reason you want to do that).
Btw, and I should have mentioned this originally with the post but as mentioned in the comments for this post you can tap S in FCP and Slip the text element right in the Timeline. Thanks for reminding me, folks!