I found https://support.dbvis.com/support/discussions/topics/1000077790 and have the very same behaviour. I could not find the context menu sporting the mentioned choice. You might want to detail the documentation for this.
I found a way to do it manually by forming the query according to your example in the documentation and adjusting the "Max Row Count" value (to bigger than 0) in the detail panel of the monitor.
Picture of the details panel
I assume you mean where the menu options are to create the row count Monitor SQLs?
They are in the Data tab right-click menu:
Thanks for getting at the issue. Oh boy do I feel stupid. I cannot reproduce not having the menu items...
I am sorry for the hassle.