Minor bug report
I just had something odd happen to me when open a file with ~ 300 lines, and therefore naturally requiring a vertical scroll bar.
The file opened and all looked normal (only the visible area of the document was displayed in the view port, a scroll bar was on the right, as expected). However, when attempting to scroll down, nothing was happening. At first I thought my Mac had frozen up, but on further inspection, I noticed that the scroll bar was actually displaying as 100% of the height of the view port, thus indicating that there was in fact nowhere to scroll.
Closing the file and re-opening it corrected the issue. It has only happened to me this once. It's probably irrelevant, but the file was opened with the Quick Open dialog (CMD + T).
EDIT | It's happening again on another file now. Seems to have just started this evening even though I've used it all day just fine.