public void redraw_canvas(){
    var window = get_window();
    if(window == null)
        return;
    unowned Cairo.Region region = window.get_clip_region();
    window.invalidate_region(region, true);
    window.process_updates(true);
}

/*
Gdk-ERROR **: The program 'IRCore' received an X Window System error.
This probably reflects a bug in the program.
The error was 'RenderBadPicture (invalid Picture parameter)'.
  (Details: serial 838 error_code 174 request_code 152 minor_code 26)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)
Trace/breakpoint trap



SOMETIMES, there's just this one:
[xcb] Unknown request in queue while dequeuing
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.


*/