The click widget works for the standard Mendix tab widget. The click can be recorded or entered manually.
To enter it manually you need to add the function”Click Widget” to your test case and use the tab page name for the parameter “Widget name”. This will be done automatically if you use the recorder.
If you do not have access to the Mendix modeler you can see the tab name using the ATS helper bookmarklet that you can find in ATS.
Hope this helps,