wxShapeFramework

"... since it looks like xsSerializable inherits from wxObject instead of
wxEvtHandler."

Since the xsSerializable is a generic persistent class object container
then it has no sense to derive it from event handler. On the other hand, I
can still implement emitting of shape events on all shapebase-related
operations like moving, sizing, hitting, etc. and those events can be
redirected directly to the shape canvas. wxSFShapeEvent holds also pointer
to source shape so a user could operate with it directly from an event
handler connected to the shape canvas. What do you think about it?

Thanks, it seems to be fine for the Canvas, but not for shapes since it
looks like xsSerializable inherits from wxObject instead of wxEvtHandler

"The current implementation requires using only inherited versions of the
FrameCanvas and Shapes in order to expose callback functionality"

It is not the truth. There are also wxSF events implemented in the library
for both shape canvas and shapes (for example for clicking or
double-clicking the shape canvas, dropping shapes to the canvas, pasting
shapes to the canvas, text shapes' content change, etc.) See the sample
projects (wxSFSample2 and wxSFSample3) and documentation. If you request
some other event, let me know.