Cannot save from source view, mime type unknown

After creating a new XHTML 1.1 document in Amaya 8.0 (Linux GTK) ("File > New >
New XHTML 1.1 Document") and making some changes in the source view, I tried to
save the changes ("File > Save as") in the source view window, but I was unable
to save the new document to a file because the mime type was set to UNKNOWN,
and the "Save as" dialogue showed "Error: invalid MIME type", however, changing
the MIME type was impossible ("The target must be an HTTP URL to use this
option"). There was no way to save the changes made in the source view to a
local file. The "Save as" dialogue from the main window shows a MIME type of
text/html, whereas the "Document Information" dialogue (main window) shows MIME
type UNKNOWN.

The document information should be shared by the various views and dialogues.

Karl-Michael