I tried a solution from below forum, but it worked only for AEM 6.3. Is there any solution for AEM 6.4?
Restricting a page to be subjected to workflow only once at a time in AEM 6.3
I agree with you, it may not be working with all the workflow launch/views or options to create workflow. But same can be implemented to handle other possibilities. I created above just for PoC to show hoe to handle above problem.
It started working after I added class cq-common-admin-timeline-toolbar-actions-workflow in column view. Now it is not working in list view. I guess we need to handle different views
It works in 6.4 as well, I just checked. Can you see any error in browser console? or which category are you using for this js.