scrollable only in vertical direction (by default, i.e. if neither
this style nor ::wxHSCROLL is specified, it scrolls in both
directions).
+ @style{wxALWAYS_SHOW_SB}
+ Since wxWidgets 2.9.5, specifying this style makes the window always
+ show its scrollbars, even if they are not used. See ShowScrollbars().
@style{wxRETAINED}
Uses a backing pixmap to speed refreshes. Motif only.
@endStyleTable