diff --git a/src/gui.c b/src/gui.c
index d7024a8..a4e2bfe 100644
--- a/src/gui.c
+++ b/src/gui.c
@@ -1407,7 +1407,7 @@
     if (!gui.shell_created)
 	return;
 
-#ifdef MSWIN
+#if defined(MSWIN) || defined(FEAT_GUI_GTK)
     /* If not setting to a user specified size and maximized, calculate the
      * number of characters that fit in the maximized window. */
     if (!mustset && gui_mch_maximized())