diff --git a/src/nsfns.m b/src/nsfns.m
index cffb599..8510327 100644
--- a/src/nsfns.m
+++ b/src/nsfns.m
@@ -671,6 +671,18 @@ x_set_tool_bar_lines (struct frame *f, Lisp_Object value, Lisp_Object oldval)
         {
           free_frame_tool_bar (f);
           FRAME_EXTERNAL_TOOL_BAR (f) = 0;
+
+          {
+            Lisp_Object fullscreen = get_frame_param (f, Qfullscreen);
+            if (EQ (fullscreen, Qmaximized))
+              {
+                store_frame_param (f, Qfullscreen, Qfullwidth);
+              }
+            else if (EQ (fullscreen, Qfullheight))
+              {
+                store_frame_param (f, Qfullscreen, Qnil);
+              }
+          }
         }
     }