group editing of sequence features

Analogous to group editing of sequences, Bernd Brandt requests that some means is provided to edit sequence features for several sequences at once.

The current 'double click to edit' only works on the feature under the specific sequence that's double clicked:
 * could use the current selection to scope the sequence features of the same type that are to be edited
 >*> would need to be able to select all the sequences containing that feature with those aligned start/end positions.

 * could tag features created at the same time so they are (optionally) edited at the same time too
 >*> define if an individual sequence feature edit will break the association
 >*> potentially allow feature 'editgroups' to be modified ?