Using the steps below, I was able to enable the Activity Stream for a custom module I created and deployed in Module Builder:
1. In your SugarCRM file system, navigate to ./custom/Extension/modules/<Custom Module>/Ext/Vardefs/ *The <Custom Module> value should be replaced with the full module name. This includes the Package Key and the Module Name value, found in Module Builder. *If you haven't created or edited any fields in Studio, you will need to create the directories presented. If you do create these directories, ensure they have the correct ownership and permissions before proceeding.
2. Create a new file, titled something like: 'activity_enabled.php' 3. In this file, add the following code:
*Here you'll need to replace <Custom Module> with the same value as step 1.
4. Save your changes to this file, then return to SugarCRM in your web browser. 5. Login as an Administrator user and navigate to Admin > Repair. 6. Click the 'Quick Repair and Rebuild' option.
Once the Quick Repair and Rebuild is completed, navigate to the ListView of your custom module. The Activity Stream button will now be enabled.
Because we made these changes in the ./custom directory, they'll be upgrade safe, so you don't have to worry about the changes reverting when you upgrade your Sugar 7 version. If you have any questions, please let me know.