diff --git a/server/src/plugin/plugin.c b/server/src/plugin/plugin.c
index 5c3e972..8a52016 100644
--- a/server/src/plugin/plugin.c
+++ b/server/src/plugin/plugin.c
@@ -40,10 +40,11 @@
 
  int pw3270_plugin_page_added(GtkWidget *terminal) {
 
- 	// Creates IPC, associate it with the terminal window.
+ 	if(!GTK_IS_V3270(terminal))
+		return EINVAL;
 
- 	g_return_val_if_fail(GTK_IS_V3270(terminal),EINVAL);
 
+ 	// Creates IPC, associate it with the terminal window.
  	// Build session name.
  	g_autofree gchar * session_name = g_strdup(v3270_get_session_name(terminal));
  	{
@@ -108,13 +109,13 @@
 
  int pw3270_plugin_page_removed(GtkWidget *terminal) {
 
- 	if(GTK_IS_V3270(terminal)) {
-		debug("%s(%p)",__FUNCTION__,g_object_get_data(G_OBJECT(terminal),"ipc-object-info"));
-		g_object_set_data(G_OBJECT(terminal), "ipc-object-info", NULL);
-		return 0;
- 	}
+ 	if(!GTK_IS_V3270(terminal))
+		return EINVAL;
+
+	debug("%s(%p)",__FUNCTION__,g_object_get_data(G_OBJECT(terminal),"ipc-object-info"));
+	g_object_set_data(G_OBJECT(terminal), "ipc-object-info", NULL);
+	return 0;
 
- 	return -1;
  }
 
  int pw3270_plugin_start(GtkWidget G_GNUC_UNUSED(*window), GtkWidget *terminal) {
--
libgit2 0.21.2