ScrolledWindow is not fully initalized after init()
Submitted by Patrik Fimml
When creating a scrolled window by other means than gtk_scrolled_window_new(), e.g. from a child widget, it is not fully initialized after its init function.
The scrollbar members as well as the adjustments are NULL, whereas various functions rely on them being objects. Adding a widget from a child class' init function, for example, produces
Gtk-CRITICAL **: gtk_range_get_adjustment: assertion `GTK_IS_RANGE (range)' failed
Set the adjustments to anything (even NULL does the trick), because gtk_scrolled_window_set_[hv]adjustment then will take care of creating adjustments and scrollbars, e.g.
g_object_set(object, "hadjustment", NULL, "vadjustment", NULL, NULL); or the appropriate C functions
init() should either create adjustments or scrollbars, or all functions using them should check them for NULL.