The command "paste pdf" was always disabled because the
condition in the following "if" statement always returns false
if (arg == "pdf" && (type = Clipboard::PdfGraphicsType))
The value of "type" is zero in this case because PdfGraphicsType is
the first enum value (and it is not set explicitly to non-zero).
An alternative patch is to put AnyGraphicsType as the first
element of enum GraphicsType, or to set the first element to a
number greater than 0.
To test the bug that this commit fixes, either copy a PDF and try to
paste with the action "paste pdf", or click on the "Edit" menu and
notice (before this commit) the terminal output "Unrecognized
graphics type: pdf".