I checked on my system. 13.0v5 and OSX 10.8.5. This is a slightly older version of OS X, but Script Manger shows the first row when I open it.
As I recall, this has been reported as a bug in FileMaker with Yosemite
If it is causing you trouble, set your System Preferences>General> "Show scroll bars" to "Always"
Same configuration, and yes, I'm seeing it too where the window is scrolled up a bit, enough to hide the first row or two. hadn't really noticed it before. Looks like the bug has been reported.
Good afternoon jml,
Thank you for taking the time to reply! I thought that might be the case, but it's comforting to have the confirmation. Have a great evening!