Starting with the release of Strategy ONE (March 2024), dossiers are also known as dashboards.
SYMPTOM
Certain users cannot add datasets or objects to a Dossier as the option to Add Data is missing in Strategy Web 10.9.
Below is an example in which Datasets can be added by the Admin user:

Below is an example in which Datasets can NOT be added by a user with the following privileges disabled: Web Manage datasets, Access data from Local, Cloud App and Databases, and Web Create new report:

STEPS TO REPRODUCE
Follow these steps to reproduce the issue in a Strategy Tutorial Project:
1. Create a user in Strategy and disable the following privileges: Web Manage datasets, Access data from Local, Cloud App and Databases, and Web Create new report
2. Create a Dossier in Web
3. In the “DATASETS” column, there is no option to add data.
CAUSE
This is working as designed in Strategy Web 10.9. The user creating the Dossier does not have sufficient privileges to add data into the Dossier.
ACTION
The following privileges need to be assigned to the user creating the Dossier in order to add data:
1. "Existing Dataset" requires "Web Manage datasets" privilege which is under Web Professional in Developer >> Administration >> User Manager >> Edit User >> Project Access.
2. "New Data" requires "Access data from Local, Cloud App and Databases" which is under Web Analyst in Developer >> Administration >> User Manager >> Edit User >> Project Access.
3. "Existing objects" requires "Web Create new report" privilege which is under Web Analyst in Developer >> Administration >> User Manager >> Edit User >> Project Access.
Article Reference Number: KB440307