Hi,

You can create a Process flow that starts when the task has been executed and thereafter does a Refresh of table B. Does that help out?

I tried something like this, but is not working. Have I done something wrong?

Have you tried using the Process flow monitor in the Developer tab of the Windows GUI? I think it might already have problems activating the document shopping_order_he… but I might be wrong.

I tried but i didn't figure out why is not refreshing the screen.

You selected activate document in your process flow. If you want to activate a document then you should also open the document in the same process flow and give the document id to a process parameter. 
 

If you change activate document to open_document you can either open a new screen (now you don't need the refresh action). Or you use open_document with the input option try use an existing document. And then do the refresh. However, if you have multiple instances of the same table opened it will open the first one and refresh that one.