TreeView tooltip use immediate control

[Stefan Salewski <mail ssalewski de>]

I have an application which use many TreeView widgets (see
http://www.ssalewski.de/PetEd.html.en). I use set_tooltip_column() to
activate tooltips at program start when widgets are created.

How can I immediately activate or deactivate tooltips for all TreeView
widgets on user action, i.e. menu operation. It should not be necessary
to terminate and restart the program.

Of course I can use a list of all TreeView widgets for accessing all and
use set_tooltip_column()...

But I guess I should solve this problem by using events? Which GTK event
is best used for this modification? Or should I emit an event myself,
when user wants to toggle tooltip display? I have no idea currently.

Thanks,

Stefan Salewski