Re: event-modifiers with control in mouse events

[Luc Teirlinck]

Stefan Monnier wrote:

   I believe what's happening is that `event-modifiers' only returns a correct
   answer if the event has already been produced by some real input
   (e.g. if you've already pressed the mouse-1 button while holding the
   control key).

Yes and it is documented, both in the docstring and in the description
of the function in `(elisp)Classifying Events'.  Both contain the
text:

    If event is a symbol that has never been used in an event that has
    been read as input in the current Emacs session, then this function
    can return nil, even when event actually has modifiers.

Sincerely,

Luc.