If you edit a symbol in the common library, how do you get existing instances to update based on the changes to the "master" symbol? Is it only when you edit the symbols in the document library that the changes are propogated & they only go to the instances in that document?
Not sure I get your question correctly but here's my experience:
Drag and drop a Symbol from the Common Library to the canvas in your PNG file. For example, drag and drop an "Anchor" from "2D objects" subfolder in Common Library.
Duplicate the Symbold a few times on the canvas, so we can see what happens next.
Now edit the first Anchor symbol you dropped to the canvas -- double-click it to enter Symbol Editing mode, and then change its fill to black or red. Exit "Edit Symbol" editing more, and see all anchors on the canvas become black (or red)! Is this what you are trying to achieve -- all symbols are udpated at once, once you edit the first instance of a specific symbol?
Hope this helps...
I was trying to get changes in the common library to upate pages in other PNG files that used the common library symbols. Now I see that you have to IMPORT a symbol from another PNG file, not from the common library, inorder for a change in a symbol in one file to propogate to other files.