Reset the cursor with Input.set_custom_mouse_cursor(null)

doc/classes/Input.xml

@@ -284,7 +284,7 @@
 			<argument index="2" name="hotspot" type="Vector2" default="Vector2( 0, 0 )">
 			</argument>
 			<description>
-				Set a custom mouse cursor image, which is only visible inside the game window. The hotspot can also be specified. See enum [code]CURSOR_*[/code] for the list of shapes.
+				Set a custom mouse cursor image, which is only visible inside the game window. The hotspot can also be specified. Passing [code]null[/code] to the image parameter resets to the system cursor. See enum [code]CURSOR_*[/code] for the list of shapes.
 			</description>
 		</method>
 		<method name="set_mouse_mode">

platform/osx/os_osx.mm

@@ -1594,6 +1594,11 @@ void OS_OSX::set_custom_mouse_cursor(const RES &p_cursor, CursorShape p_shape, c
 		if (p_shape == CURSOR_ARROW) {
 			[cursor set];
 		}
+	} else {
+		// Reset to default system cursor
+		cursors[p_shape] = NULL;
+		cursor_shape = CURSOR_MAX;
+		set_cursor_shape(p_shape);
 	}
 }
 

platform/windows/os_windows.cpp

@@ -2117,6 +2117,11 @@ void OS_Windows::set_custom_mouse_cursor(const RES &p_cursor, CursorShape p_shap
 		if (hXorMask != NULL) {
 			DeleteObject(hXorMask);
 		}
+	} else {
+		// Reset to default system cursor
+		cursors[p_shape] = NULL;
+		cursor_shape = CURSOR_MAX;
+		set_cursor_shape(p_shape);
 	}
 }
 

platform/x11/os_x11.cpp

@@ -2486,6 +2486,14 @@ void OS_X11::set_custom_mouse_cursor(const RES &p_cursor, CursorShape p_shape, c
 		if (p_shape == CURSOR_ARROW) {
 			XDefineCursor(x11_display, x11_window, cursors[p_shape]);
 		}
+	} else {
+		// Reset to default system cursor
+		if (img[p_shape]) {
+			cursors[p_shape] = XcursorImageLoadCursor(x11_display, img[p_shape]);
+		}
+
+		current_cursor = CURSOR_MAX;
+		set_cursor_shape(p_shape);
 	}
 }