How to Reproduce:
1. Right click a scene to display the context menu.
2. Click "Object Properties" from the context menu.
3. The "Object Properties" window appears.
4. In the comment textarea of the "Object Properties" window, you cannot press the enter key to add another line of comments.
(additionaly, it'd be nice if you could resize this dialog...but I digress...just wanted to bring this bug to your attention)
System:
Windows 7 Ultimate 64-Bit Edition