1. Have a file with a long name in the middle of a folder that has a lot of other files (scrollable page).
2. Click the file once to highlight the text, then while the cursor is within the text entry box, scroll the long file name up and down with your two fingers.

Result:
The page itself will move, instead of the long name you're selecting.

It works perfectly on the Desktop area, likely because I can't scroll the desktop itself up and down.