GtkExpander weird behavior question

[Jean-Dominique Frattini <dagecko83 gmail com>]

Currently (and since many versions of gtk+) when a GtkExpander is not
expanded, all its content still react to mouse actions. So when moving
up/down a page with mouse wheel, all what is inside the not expanded
GtkExpander are reacting (spinbuttons change values, combobox change
values...). The mouse pointer should be at the place where the widget
should have been visible if the GtkExpander was expanded. This is very
annoying. So I manage myself this behavior (I make the expander content not
sensitive when it is not expanded). This is cumbersome since I have many
expanders.
Is this made on purpose ? Should I report a bug ?

Thank you.