[gtkmm] Tooltips & TextView

[Barnaby Gray <bee pickle me uk>]

(Apologies for the onslaught of TextView related questions today,
hopefully someone can answer at least one of them..)

I'd like to customise the text on the tool tip to the particular row
the pointer is floating over when it pops up (and ideally selectively
not have tool tips popping up for some rows), does anyone know if this
is possible, and what the best approach is.

Cheers,

Barnaby