Abstract interface for bar-size handler classes. These objects receive notifications whenever the docking state of the bar is changed, thus they provide the possibility to adjust the values in cbDimInfo::mSizes accordingly. Specific handlers can be hooked up to specific types of bar.
to multiple bars, it's instance is reference-counted Default constructor. The initial reference count is 0, since the handler is not used until the first invocation of AddRef().
Increments the reference count.
void OnChangeBarState(cbBarInfo* pBar, int newState)
Responds to "bar-state-changes" notifications.
void OnResizeBar(cbBarInfo* pBar, const wxSize& given, wxSize& preferred)
Responds to bar resize notifications.
Decrements the reference count, and if the count is at zero, delete 'this'.