An object for managing a collection of tooltips.
Tooltips are the messages that appear next to a widget when the mouse
pointer is held over it for a short amount of time. They are especially
helpful for adding more verbose descriptions of things such as buttons
in a toolbar.
An individual tooltip belongs to a group of tooltips. A group is created
with the constructor. Every tooltip in the group can then be turned off
with a call to disable() and
enabled with enable() .
Tooltips can only be set on widgets which have their own X window.
To add a tooltip to a widget that doesn't have its own window, place
the widget inside a GtkEventBox and add a tooltip
to that instead.
Creates a new tooltips object.