diff -r 749a32e91513 -r 4637da12bc6c ui/gtk/headerbar.c
--- a/ui/gtk/headerbar.c	Wed Jun 17 20:42:21 2026 +0200
+++ b/ui/gtk/headerbar.c	Wed Jun 17 20:54:22 2026 +0200
@@ -120,6 +120,9 @@
         case UI_TOOLBAR_TOGGLEITEM: {
             return ui_add_headerbar_toggleitem(headerbar, box, (UiToolbarToggleItem*)i, obj, pos);
         }
+        case UI_TOOLBAR_CONTENT_TOGGLEITEM: {
+            return ui_add_headerbar_content_toggleitem(headerbar, box, (UiToolbarContentToggleItem*)i, obj, pos);
+        }
         case UI_TOOLBAR_MENU: {
             return ui_add_headerbar_menu(headerbar, box, (UiToolbarMenuItem*)i, obj, pos);
         }
@@ -206,6 +209,33 @@
     return button;
 }
 
+GtkWidget* ui_add_headerbar_content_toggleitem(
+        GtkWidget *headerbar,
+        GtkWidget *box,
+        UiToolbarContentToggleItem *item,
+        UiObject *obj,
+        enum UiToolbarPos pos)
+{
+    UiContentToggleArgs args = { 0 };
+    args.label0 = item->args.label0;
+    args.icon0 = item->args.icon0;
+    args.tooltip0 = item->args.tooltip0;
+    args.label1 = item->args.label1;
+    args.icon1 = item->args.icon1;
+    args.tooltip1 = item->args.tooltip1;
+    args.varname = item->args.varname;
+    args.onchange = item->args.onchange;
+    args.onchangedata = item->args.onchangedata;
+    args.action = item->args.action;
+    args.istogglebutton = item->args.istogglebutton;
+    args.toggled_by_state = item->args.toggled_by_state;
+    
+    GtkWidget *button = ui_create_content_togglebutton(obj, &args);
+    WIDGET_ADD_CSS_CLASS(button, "flat");
+    headerbar_add(headerbar, box, button, pos);
+    return button;
+}
+
 GtkWidget* ui_add_headerbar_menu(
         GtkWidget *headerbar,
         GtkWidget *box,