diff --git a/src/calendar.c b/src/calendar.c
index 0e6cb32..9f82cc6 100644
--- a/src/calendar.c
+++ b/src/calendar.c
@@ -153,7 +153,7 @@ zenity_calendar_dialog_response (GtkWidget *widget, int response, gpointer data)
       break;
 
     default:
-      if (response < g_strv_length(zen_data->extra_label))
+      if (zen_data->extra_label && response < g_strv_length(zen_data->extra_label))
         printf("%s\n",zen_data->extra_label[response]);
       zen_data->exit_code = zenity_util_return_exit_code (ZENITY_ESC);
       break;
diff --git a/src/color.c b/src/color.c
index 05898c4..ae47b19 100644
--- a/src/color.c
+++ b/src/color.c
@@ -104,7 +104,7 @@ zenity_colorselection_dialog_response (GtkWidget *widget, int response, gpointer
       break;
 
     default:
-      if (response < g_strv_length(zen_data->extra_label))
+      if (zen_data->extra_label && response < g_strv_length(zen_data->extra_label))
         printf("%s\n",zen_data->extra_label[response]);
       zen_data->exit_code = zenity_util_return_exit_code (ZENITY_ESC);
       break;
diff --git a/src/entry.c b/src/entry.c
index 8036726..8e47ebd 100644
--- a/src/entry.c
+++ b/src/entry.c
@@ -192,7 +192,7 @@ zenity_entry_dialog_response (GtkWidget *widget, int response, gpointer data)
       break;
 
     default:
-      if (response < g_strv_length(zen_data->extra_label))
+      if (zen_data->extra_label && response < g_strv_length(zen_data->extra_label))
         printf("%s\n",zen_data->extra_label[response]);
       zen_data->exit_code = zenity_util_return_exit_code (ZENITY_ESC);
       break;
diff --git a/src/fileselection.c b/src/fileselection.c
index 3ccd11d..27db0f4 100644
--- a/src/fileselection.c
+++ b/src/fileselection.c
@@ -189,7 +189,7 @@ zenity_fileselection_dialog_response (GtkWidget *widget, int response, gpointer
       break;
 
     default:
-      if (response < g_strv_length(zen_data->extra_label))
+      if (zen_data->extra_label && response < g_strv_length(zen_data->extra_label))
         printf("%s\n",zen_data->extra_label[response]);
       zen_data->exit_code = zenity_util_return_exit_code (ZENITY_ESC);
       break;
diff --git a/src/forms.c b/src/forms.c
index 53e9423..5241780 100644
--- a/src/forms.c
+++ b/src/forms.c
@@ -371,7 +371,7 @@ zenity_forms_dialog_response (GtkWidget *widget, int response, gpointer data)
       break;
 
     default:
-      if (response < g_strv_length(zen_data->extra_label))
+      if (zen_data->extra_label && response < g_strv_length(zen_data->extra_label))
         printf("%s\n",zen_data->extra_label[response]);
       zen_data->exit_code = zenity_util_return_exit_code (ZENITY_ESC);
       break;
diff --git a/src/msg.c b/src/msg.c
index ddaab26..da4783d 100644
--- a/src/msg.c
+++ b/src/msg.c
@@ -244,7 +244,7 @@ zenity_msg_dialog_response (GtkWidget *widget, int response, gpointer data)
       break;
 
     default:
-      if (response < g_strv_length(zen_data->extra_label))
+      if (zen_data->extra_label && response < g_strv_length(zen_data->extra_label))
         printf("%s\n",zen_data->extra_label[response]);
       zen_data->exit_code = zenity_util_return_exit_code (ZENITY_ESC);
       break;
diff --git a/src/password.c b/src/password.c
index 1d17d91..d8f492f 100644
--- a/src/password.c
+++ b/src/password.c
@@ -179,7 +179,7 @@ zenity_password_dialog_response (GtkWidget *widget, int response, gpointer data)
       break;
 
     default:
-      if (response < g_strv_length(zen_data->extra_label))
+      if (zen_data->extra_label && response < g_strv_length(zen_data->extra_label))
         printf("%s\n",zen_data->extra_label[response]);
       zen_data->exit_code = zenity_util_return_exit_code (ZENITY_ESC);
       break;
diff --git a/src/progress.c b/src/progress.c
index 8e458c6..4995c5f 100644
--- a/src/progress.c
+++ b/src/progress.c
@@ -393,7 +393,7 @@ zenity_progress_dialog_response (GtkWidget *widget, int response, gpointer data)
       zenity_util_exit_code_with_data (ZENITY_TIMEOUT, zen_data);
       break;
     default:
-      if (response < g_strv_length(zen_data->extra_label))
+      if (zen_data->extra_label && response < g_strv_length(zen_data->extra_label))
         printf("%s\n",zen_data->extra_label[response]);
       zen_data->exit_code = zenity_util_return_exit_code (ZENITY_ESC);
       break;
diff --git a/src/scale.c b/src/scale.c
index cc9ce10..3eb5c17 100644
--- a/src/scale.c
+++ b/src/scale.c
@@ -149,7 +149,7 @@ zenity_scale_dialog_response (GtkWidget *widget, int response, gpointer data)
       break;
 
     default:
-      if (response < g_strv_length(zen_data->extra_label))
+      if (zen_data->extra_label && response < g_strv_length(zen_data->extra_label))
         printf("%s\n",zen_data->extra_label[response]);
       zen_data->exit_code = zenity_util_return_exit_code (ZENITY_ESC);
       break;
diff --git a/src/text.c b/src/text.c
index 5657f21..1deecc6 100644
--- a/src/text.c
+++ b/src/text.c
@@ -388,7 +388,7 @@ zenity_text_dialog_response (GtkWidget *widget, int response, gpointer data)
       break;
 
     default:
-      if (response < g_strv_length(zen_data->extra_label))
+      if (zen_data->extra_label && response < g_strv_length(zen_data->extra_label))
         printf("%s\n",zen_data->extra_label[response]);
       zenity_util_exit_code_with_data(ZENITY_ESC, zen_data);
       break;
diff --git a/src/tree.c b/src/tree.c
index 7398fc2..058b6b6 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -711,7 +711,7 @@ zenity_tree_dialog_response (GtkWidget *widget, int response, gpointer data)
       break;
 
     default:
-      if (response < g_strv_length(zen_data->extra_label))
+      if (zen_data->extra_label && response < g_strv_length(zen_data->extra_label))
         printf("%s\n",zen_data->extra_label[response]);
       zen_data->exit_code = zenity_util_return_exit_code (ZENITY_ESC);
       break;