This is a known issue.
For More Information see: Auto-Scrolling in Script Workspace makes it pretty much unusable for long scripts.
This is one of many acknowledged bugs that can be found in the Known Bug List thread here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: https://www.dropbox.com/s/jt09b82i0xijbu3/FMP%20Bugs.zip
Thank you, PhilModJunk.
Thank you for your posts.
As "PhilModJunk" pointed out (Thank you!), this is a known issue, and our Development and Testing departments are aware of this issue. I have attached your post to the original report, and when more information becomes available, I will post again.
Good, thank you
This issue has been addressed in FileMaker Pro 15.