[wxGTK] wxTLW not scrollable (was: segfault with Dialog)

[Robert Roebling]

>  Ok. I'd just like to make sure that the code fails with an intelligible
> error message instead of crashing then. What would be the best way to do
> it? I see
> 
> 1. Overriding SetScrollbar() &c at wxTLW level to assert and do nothing
>    (in particular, not crash)
> 
> 2. Adding checks that the m_scrollBar elements are non-NULL in wxWindow
>    itself.
> 
> If wxTLW is the only case in which m_scrollBar[x] can be NULL

No, it can be NULL in all wxControls so it must be 2,

 Robert