matplotlib
diff --git a/‎lib/matplotlib/backend_bases.py
Copy file name to clipboardExpand all lines: lib/matplotlib/backend_bases.py
+10-5Lines changed: 10 additions & 5 deletions b/‎lib/matplotlib/backend_bases.py
Copy file name to clipboardExpand all lines: lib/matplotlib/backend_bases.py
+10-5Lines changed: 10 additions & 5 deletions
diff --git a/‎lib/matplotlib/backend_tools.py
Copy file name to clipboardExpand all lines: lib/matplotlib/backend_tools.py
+10-5Lines changed: 10 additions & 5 deletions b/‎lib/matplotlib/backend_tools.py
Copy file name to clipboardExpand all lines: lib/matplotlib/backend_tools.py
+10-5Lines changed: 10 additions & 5 deletions
@@ -2541,9 +2541,13 @@ def _get_uniform_gridstate(ticks):
 
     ax = event.inaxes
     # toggle major grids in current axes (default key 'g')
-    # Both here and below (for 'G'), we do nothing is the grids are not in a
-    # uniform state, to avoid messing up user customization.
-    if event.key in grid_keys:
+    # Both here and below (for 'G'), we do nothing if *any* grid (major or
+    # minor, x or y) is not in a uniform state, to avoid messing up user
+    # customization.
+    if (event.key in grid_keys
+            # Exclude minor grids not in a uniform state.
+            and None not in [_get_uniform_gridstate(ax.xaxis.minorTicks),
+                             _get_uniform_gridstate(ax.yaxis.minorTicks)]):
         x_state = _get_uniform_gridstate(ax.xaxis.majorTicks)
         y_state = _get_uniform_gridstate(ax.yaxis.majorTicks)
         cycle = [(False, False), (True, False), (True, True), (False, True)]
@@ -2554,8 +2558,9 @@ def _get_uniform_gridstate(ticks):
             # Exclude major grids not in a uniform state.
             pass
         else:
-            ax.grid(x_state, which="major", axis="x")
-            ax.grid(y_state, which="major", axis="y")
+            # If turning major grids off, also turn minor grids off.
+            ax.grid(x_state, which="major" if x_state else "both", axis="x")
+            ax.grid(y_state, which="major" if y_state else "both", axis="y")
             canvas.draw_idle()
     # toggle major and minor grids in current axes (default key 'G')
     if (event.key in grid_minor_keys
 
@@ -430,12 +430,12 @@ def trigger(self, sender, event, data=None):
         if ax is None:
             return
         try:
-            x_state, y_state, which = self._get_next_grid_states(ax)
+            x_state, x_which, y_state, y_which = self._get_next_grid_states(ax)
         except ValueError:
             pass
         else:
-            ax.grid(x_state, which=which, axis="x")
-            ax.grid(y_state, which=which, axis="y")
+            ax.grid(x_state, which=x_which, axis="x")
+            ax.grid(y_state, which=y_which, axis="y")
             ax.figure.canvas.draw_idle()
 
     @staticmethod
@@ -461,13 +461,18 @@ class ToolGrid(_ToolGridBase):
     default_keymap = rcParams['keymap.grid']
 
     def _get_next_grid_states(self, ax):
+        if None in map(self._get_uniform_grid_state,
+                       [ax.xaxis.minorTicks, ax.yaxis.minorTicks]):
+            # Bail out if minor grids are not in a uniform state.
+            raise ValueError
         x_state, y_state = map(self._get_uniform_grid_state,
                                [ax.xaxis.majorTicks, ax.yaxis.majorTicks])
         cycle = self._cycle
         # Bail out (via ValueError) if major grids are not in a uniform state.
         x_state, y_state = (
             cycle[(cycle.index((x_state, y_state)) + 1) % len(cycle)])
-        return x_state, y_state, "major"
+        return (x_state, "major" if x_state else "both",
+                y_state, "major" if y_state else "both")
 
 
 class ToolMinorGrid(_ToolGridBase):
@@ -487,7 +492,7 @@ def _get_next_grid_states(self, ax):
         # Bail out (via ValueError) if minor grids are not in a uniform state.
         x_state, y_state = (
             cycle[(cycle.index((x_state, y_state)) + 1) % len(cycle)])
-        return x_state, y_state, "both"
+        return x_state, "both", y_state, "both"
 
 
 class ToolFullScreen(ToolToggleBase):