SYMPTOM:
In Strategy Web 9.x and 10.x, it is possible to save export options to the report definition of a specific report by performing an export with those settings and then saving the report. However, after only making changes to a report's export options, the "Save" button remains inactive, or greyed out, in the report interface, indicating that no changes have been made, like shown below.

STEPS TO REPRODUCE:
Follow these steps in Strategy Web 9.x and 10.x to reproduce the issue in a Strategy Tutorial project.
CAUSE:
This is a known issue in Strategy Web 9.x and 10.x.
ACTION:
Contact Strategy Technical Support for an update on this issue.
WORKAROUND:
Use the "Save As" option instead, from the "home" drop-down menu, and overwrite the report to save the export options to the report definition, as shown below.

Or make a quick change on the report's formatting and undo it, to enable the Save button.
The Strategy Internal Reference Number for the issue discussed in this technical note is 998988.