It was already there, but I like it here better.

indra/newview/skins/default/xui/en/panel_preferences_advanced.xml

@@ -191,16 +191,6 @@
      name="allow_multiple_viewer_check"
      top_pad="20"
      width="237"/>
-    <check_box
-     control_name="ForceShowGrid"
-     follows="top|left"
-     height="15"
-     label="Show Grid Selection at login"
-     layout="topleft"
-     left="30"
-     name="show_grid_selection_check"
-     top_pad="5"
-     width="237"/>
     <check_box
      control_name="UseDebugMenus"
      follows="top|left"

indra/newview/skins/default/xui/en/panel_preferences_grids.xml

@@ -120,10 +120,10 @@
    control_name="ForceShowGrid"
    height="20"
    follows="left|top"
-   label="Show grid selection on login screen"
+   label="Show Grid Selection at Login"
    layout="topleft"
    left="30"
-   name="ForceShowGrid"
+   name="show_grid_selection_check"
    tool_tip="Show grid selection on login screen to login to other worlds"
    width="280"
    top="310" />