You might want to create a security rule, you will need to have the object id, a very basic sample for this implementation would be to create the bookmark , then go to the repository DB
SELECT * FROM public."AppObjects" where "ObjectType" = 'bookmark';
Get the value of the EngineObjectId and create the rule
Or you can also use the resource name, for example:
((resource.name="Session Details - Today (\"2019-07-23\")" and user.name="user1"))
Just be sure you are applying the rule to app objects.
Note: Debugging and writing custom security rules cannot be carried out by Qlik Support directly. No Support or maintenance is implied or provided. Further customization is expected to be necessary and it is the responsibility of the end administrator to test and implement an appropriate rule for their specific use case. The example provided above is provided as is, and we suggest joining our Qlik Community for access to more best practices and solutions. For direct implementation advice, our Consulting Service and PreSales are available to assist.
Please also refer to the following article that is more specific about the objecttype:
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