ACA/AMEP: PASTEBLOCK Observation

I have been working on files that were created by others recently, and they contain a large number of Block References created using the PASTEBLOCK command, and left with the random name that gets assigned to the Block Definition by the PASTEBLOCK command. The names all start with A$C, followed by eight characters that appear to be a hexadecimal number. I find this very annoying, as you have no idea what is in any of these blocks, whereas you might if a meaningful name had been given.

Part of my current task required me to find things inside these annoying Block References, so I have been WBLOCKing them out to separate files and then opening those files to view the contents in isolation from all of the other things in the original file. I made an interesting discovery: when opening these files, the file name does not appear in the title area of the AutoCAD window and, in AutoCAD Architecture 2014 and 2016 (and, I suspect, all other versions that have File tabs), a file tab is not generated for these files. They are listed by the Switch Windows tool on the View ribbon tab, on the Windows panel, and they also appear in the Application Menu's Recent Documents list. So why do they not have drawing tabs or have their names in the title bar?

I thought there might be something wrong with my installation, so I did some admittedly brief searching on the Internet and in the online Help, and did not find any mention of this "situation." Surely I cannot be the first person to try this; perhaps I am the only one who thought it was odd.

It does not appear to be anything inside the WBLOCKed file itself. If I save the file under a different name, that does not follow the format of A$C followed by a hexadecimal number, and open that file, the file name will appear in the title area and a drawing tab will be generated. If I manually create a file and save it with a name that does follow that format (the length of the hexadecimal number does not appear to matter; so long as all of the characters that follow the initial A$C are taken from the numerals 0-9 and the letters A-F), when opened, the file name will not appear in the title area and a drawing tab will not be created.

This is not that big of a deal; I am writing this so that when I come across this in five years, having forgotten about it in the mean time, there will be at least one Internet source that discusses it.