Fix a zoom fit by double-click issue

When clicking on a page that is zoomed so that it does not fit into
window, the page will jump up/down on every click. Zoom fit by double-
clicking the page does not work then.

pdfarranger/pdfarranger.py

@@ -1839,7 +1839,8 @@ def iv_button_press_event(self, iconview, event):
             selection = iconview.get_selected_items()
             if self.click_path and self.click_path in selection:
                 self.pressed_button = event
-                self.iconview.set_cursor(self.click_path, None, False)
+                if iconview.get_cursor()[1] != self.click_path:
+                    self.iconview.set_cursor(self.click_path, None, False)
                 return 1  # prevent propagation i.e. (de-)selection
 
         # Display right click menu