Fix for latest 9.x builds

Author: tannewt

Matrix_Portal_S3_Message_Board/lib/messageboard/doublebuffer.py

@@ -37,7 +37,7 @@ def __init__(self, display, width, height, shader=None, bit_depth=16):
         self._buffer_group[1].append(buffer1_sprite)
 
     def show(self, swap=True):
-        self.display.show(self._buffer_group[self._active_buffer])
+        self.display.root_group = self._buffer_group[self._active_buffer]
         if swap:
             self.swap()