diff --git a/source/libublsettings-gtk3-misc.c b/source/libublsettings-gtk3-misc.c
index ccf2968..080e4af 100644
--- a/source/libublsettings-gtk3-misc.c
+++ b/source/libublsettings-gtk3-misc.c
@@ -277,6 +277,7 @@ void yon_on_text_insert_only_digits(GtkEditable *editable, const gchar *text, gi
 
 void yon_on_insert_restricted_check(GtkEditable *editable, const gchar *text, gint length, gint *position, gpointer){
         gchar *new_text = g_new(gchar, length + 1);
+        memset(new_text,0,length+1);
     gint i, j = 0;
 
     for (i = 0; i < length; i++) {
@@ -303,6 +304,7 @@ void yon_gtk_entry_block_restricted_symbols(GtkEntry *target){
 
 void yon_on_insert_languages(GtkEditable *editable, const gchar *text, gint length, gint *position, gpointer){
         gchar *new_text = g_new(gchar, length + 1);
+        memset(new_text,0,length+1);
     gint i, j = 0;
 
     for (i = 0; i < length; i++) {
@@ -329,6 +331,7 @@ void yon_gtk_entry_block_languages(GtkEntry *target){
 
 void yon_on_insert_custom_restricted_check(GtkEditable *editable, const gchar *text, gint length, gint *position, char *symbols){
         gchar *new_text = g_new(gchar, length + 1);
+        memset(new_text,0,length+1);
     gint i, j = 0;
 
     for (i = 0; i < length; i++) {
@@ -353,6 +356,30 @@ void yon_gtk_entry_block_symbols(GtkEntry *target, char *symbols){
     g_signal_connect(G_OBJECT(target),"insert-text",G_CALLBACK(yon_on_insert_custom_restricted_check),yon_char_new(symbols));
 }
 
+void yon_on_insert_lowercase_check(GtkEditable *editable, const gchar *text, gint length, gint *position, char *symbols){
+    gchar *new_text = g_new(gchar, length + 1);
+        memset(new_text,0,length+1);
+    gint i;
+
+    for (i = 0; i < length; i++) {
+        if (text[i]>=97&&text[i]<=122) {
+            new_text[i]=text[i]-32;
+        } else {
+            new_text[i] = text[i];
+        }
+    }
+
+        g_signal_handlers_block_by_func(editable, G_CALLBACK(yon_on_insert_lowercase_check), NULL);
+        gtk_editable_insert_text(editable, new_text, strlen(text), position);
+        g_signal_handlers_unblock_by_func(editable, G_CALLBACK(yon_on_insert_lowercase_check), NULL);
+        g_signal_stop_emission_by_name(editable, "insert-text");
+}
+
+void yon_gtk_entry_block_lowercase(GtkEntry *target){
+    g_return_if_fail(GTK_IS_ENTRY(target));
+    g_signal_connect(G_OBJECT(target),"insert-text",G_CALLBACK(yon_on_insert_lowercase_check),NULL);
+}
+
 void _yon_on_gtk_revealer_set_from_switch(GtkSwitch *target, int status, GtkRevealer *revealer){
     gtk_revealer_set_reveal_child(revealer,status);
     gtk_revealer_set_transition_type(revealer,status?GTK_REVEALER_TRANSITION_TYPE_SLIDE_DOWN:GTK_REVEALER_TRANSITION_TYPE_SLIDE_UP);
diff --git a/source/libublsettings-gtk3.h b/source/libublsettings-gtk3.h
index 9c5527b..a6d98cf 100644
--- a/source/libublsettings-gtk3.h
+++ b/source/libublsettings-gtk3.h
@@ -503,6 +503,8 @@ void yon_gtk_entry_block_languages(GtkEntry *target);
 
 void yon_gtk_entry_block_symbols(GtkEntry *target, char *symbols);
 
+void yon_gtk_entry_block_lowercase(GtkEntry *target);
+
 // GtkTreeStore section
 
 dictionary *yon_gtk_tree_store_get_children(GtkTreeStore *tree, GtkTreeIter *parent,int column);