(i also used v 4,15,3)
So , blueprint edit is complete blank.
In menu under window is available only "class default "(reset layout does nothing).
But if i make new or child of that blueprint , for first open it has everything in it , after closing and reopening it is again blank forever ,
I did update engine also uninstalled and reinstalled,
in other projects it shows same behavior.
One think i noticed is that when its blank under “window” is called defaults editor however in first time opened it says Graph Editor
here are some pics