diff --git a/src/gui.c b/src/gui.c
index 749dd612db..48e5d823c4 100644
--- a/src/gui.c
+++ b/src/gui.c
@@ -687,11 +687,17 @@ gui_init(void)
     gui.shell_created = TRUE;
 
 #ifndef FEAT_GUI_GTK
+#ifdef FEAT_GUI_MACVIM
+    // The below code setting gui_set_shellsize breaks guioption-k, so patching
+    // around it here by passing TRUE to muset.
+    gui_set_shellsize(TRUE, TRUE, RESIZE_BOTH);
+#else
     // Set the shell size, adjusted for the screen size.  For GTK this only
     // works after the shell has been opened, thus it is further down.
     // For MS-Windows pass FALSE for "mustset" to make --windowid work.
     gui_set_shellsize(FALSE, TRUE, RESIZE_BOTH);
 #endif
+#endif
 #if defined(FEAT_GUI_MOTIF) && defined(FEAT_MENU)
     /* Need to set the size of the menubar after all the menus have been
      * created. */