I want to open another instance of an already opened file using Acrobat pro 2017. This version has tabbed display of files. I can open the next instance in another window, bot not in the same window under another tab. There is a work around to it in the forum discussion. https://forums.adobe.com/message/11222204
But this is not an elegant method. I hope Adobe will provide the function that will allow it to be open in a new tab.