I have not found problems within C::B (until now) with your modifications.
My intention was just to remember you that Miguel Gimenez had identified the problem some time ago. In my C::B version, I tried to solve the problem by simply adding #if ... #else... #endif. Like that, I'm (almost) sure that the binary code is the same as previously for wx 3.1.3 and specifically adapted for wx 3.1.4 and +.
I don't know why this paint event has been added. Is it useful or not, I don't know. May be only the original author can say why he added this event.
If it works without any problem, of course the code can (and must) stay like that.
gd_on
PS : difficult for me to try to make a fail as in my application : context is totally different (I work within a wxsglcanvas window !)