TIBCO Spotfire Information Modeler license controls the Data Source Tab in the Information Designer.
You can enable or disable this via TIBCO Spotfire Administration Manager.

1)Logon to the Spotfire Analyst, user should be a Spotfire Administrator
2)Goto Tools>>Administration Manager>>Groups & Licenses 
3)Select the group that you would want to give "Create Data Source" access
4)Enable the "TIBCO Spotfire Information Modeler" License as shown in the attached screenshot "Data Source License.png"



If you only have the "Create Information Link" feature from the TIBCO Spotfire Analyst license as shown in the attached screenshot, this gives you access to the Tools > Information Designer menu option, from which you can use data sources and elements that other people have set up and create new information links. However, to set up your own data sources and elements, you must also have the TIBCO Spotfire Information Modeler license.