- Returns the icon with the given size; if no such icon exists, returns
- the icon with size @c wxSYS_ICON_X and @c wxSYS_ICON_Y; if no such icon
- exists, returns the first icon in the bundle.
+ Returns the icon with the given size.
+
+ If @a size is ::wxDefaultSize, it is interpreted as the standard system
+ icon size, i.e. the size returned by wxSystemSettings::GetMetric() for
+ @c wxSYS_ICON_X and @c wxSYS_ICON_Y.
+
+ If the bundle contains an icon with exactly the requested size, it's
+ always returned. Otherwise, the behaviour depends on the flags. If only
+ ::FALLBACK_NONE is given, the function returns an invalid icon. If
+ ::FALLBACK_SYSTEM is given, it tries to find the icon of standard
+ system size, regardless of the size passed as parameter. Otherwise, or
+ if the icon system size is not found neither, but
+ ::FALLBACK_NEAREST_LARGER flag is specified, the function returns the
+ smallest icon of the size larger than the requested one or, if this
+ fails too, just the icon closest to the specified size.