Progress bar Blocking is not working

I have a microflow call on an actionButton and the microflow settings has call type- Asynchronous and Show Progress bar- Blocking. But still progress bar is not blocking the background and i am able click and do actions in the background while microflow is been executed. What might be the reason for this? Or how can i resolve it? 
1 answers

I couldn't think of a use case for "aynchronous" processing and blocking the UI in the meantime. What's the rationale for your combination?

Typically Blocking goes hand in hand with synchronous processing.