Delay refresh until initialized
Delay refresh until initialized

on_idle can be called too early on wxGtk3/X11.
Check for m_initialized before refreshing.

prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r