Multiple formats on clipboard

["Neil Hodgson" <neilh hare net au>]

   When cutting and copying in my application, I'd like to be able to
include the data in both standard string format and an application specific
format. On MacOS or Windows you open the clipboard and add one format and
then the other. I looked at the gtk_selection API and even read the
implementation but could not work out how to do this. Reading the
implementation of gtk_selection_data_set shows that it can't be called twice
as the second call overwrites the first.

   So, thinking 'Gnumeric must be able to do this' I downloaded Gnumeric's
source only to find that it doesn't - it uses rich copy and paste (formulas,
styling and values) internally and renders to text for other apps, including
other instances of Gnumeric.

   Does anyone know how to solve this or work around it? I've thought of
adding the application specific format after a \0 but haven't tried it yet.

   Neil