Assuming there's 2 page components: 1 form (with selectbox) and the other is the CRUD, use the Ajax & Events. Once the form clicked on submit/save, trigger an ajax event. set CRUD Ajax Triggering with the conditional parameters (if param = something) , show CRUD component else, use "When Not Match Trigger Event Name", create another event to hide CRUD Component

Thanks for your response. The problem with this approach is that when you have the selectbox in a form then a table will be created in the database corresponding to the form and a table column for the selectbox. I don't want all these. I don't want to store the selected option. It is an overkill and unnecessary. Also with this approach there is one more unnecessary click than I want. After the selection you have to submit the form. No. I need the event of select not the submit to show or hide the CRUD form.

The only approach I can think of is to use the HTML page component to create a select input and then to write javascript in the select change event to show or hide the CRUD. But I wanted a no code solution if there was one.