Verifying custom gadgets
Only the owner of a spreadsheet can view an unverified custom gadget. By default, the gadget will be inactive when a collaborator views it or when the spreadsheet gets published.
If you'd like a custom gadget to be viewable within a spreadsheet by your collaborators, or by anyone when the spreadsheet is published, please send it to us. In the comments section of the form, specify whether you want this gadget to be available for anyone using Google Docs Spreadsheets.
Learn more about developing a gadget.