I have a PowerPoint file with 10 successfully created slides that are linked charts to trusted source files.

I am now trying to add an 11th slide with a new chart, created in a file that is also in the trusted source folder, but when I copy (right click - copy) the chart, then go to the PPT file and try to Paste Special Link, the LINK box is grayed out. For a while, even the Paste Special icon was grayed out, but once it came back (after what? who knows) the LINK box remains elusive.

I'm confused. I was able to develop the PPT file over time - adding charts willy-nilly, now all of a sudden I can't?