used correct refresh functions to make it work for different layer types

Author: jo-mueller

src/napari_matplotlib/histogram.py

@@ -175,8 +175,11 @@ def draw(self) -> None:
             self.layers[0].color = self.x_axis_key
         else:
             colormap = None
+
+        # apply new colors to the layer
         self.viewer.layers[self.layers[0].name].refresh_colors(True)
-        
+        self.viewer.layers[self.layers[0].name].refresh()
+
         # Draw the histogram
         data, x_axis_name = self._get_data()