The form actions are disabled after cancelling the 'File exists' dialogue that is generated by the file manager form element.

Replication steps:

1. Create a new SCORM activity
2. Add any SCORM package.
3. Without removing the added package, add the same SCORM package on top of the previous one via drag-and-drop.
4. A box will be displayed: "There is already a file called .....". OVERWRITE-CANCEL
5. Press CANCEL
6. From now on, form actions are disabled.

The same behavior can be replicated in other forms utilizing the file manager element.