org-agenda-mouse-1-follows-link

org-agenda-mouse-1-follows-link is a variable defined in `org-agenda.el'.
Its value is

nil

Documentation:
Non-nil means mouse-1 on a link will follow the link in the agenda.
A longer mouse click will still set point. Does not work on XEmacs.
Needs to be set before org.el is loaded.

You can customize this variable.