Above the box, on the right hand side, there's an icon of a little blue arrow with red brackets around it, called "Toggle View".
This switches between the automatically-fitting-the-words-in mode, and another mode where you have to use a little scroll bar across the bottom to move across and see the rest of the line.
Assuming you've not already gone into that mode (and just not noticed the scroll bar) you could try clicking it to see if it brings up the scroll bar and lets you move across to see the rest of your text.