diff -r a40c1ec7883d -r b0962e5fc125 ui/common/args.c
--- a/ui/common/args.c	Fri Aug 28 20:27:23 2026 +0200
+++ b/ui/common/args.c	Tue Sep 01 19:41:45 2026 +0200
@@ -191,6 +191,98 @@
 }
 
 
+/* ---------------------------- UiHeaderbarArgs ---------------------------- */
+
+UiHeaderbarArgs* ui_headerbar_args_new(void) {
+    UiHeaderbarArgs *args = malloc(sizeof(UiHeaderbarArgs));
+    memset(args, 0, sizeof(UiHeaderbarArgs));
+    return args;
+}
+
+void ui_headerbar_args_set_fill(UiHeaderbarArgs *args, UiBool fill) {
+    args->fill = fill;
+}
+
+void ui_headerbar_args_set_hexpand(UiHeaderbarArgs *args, UiBool value) {
+    args->hexpand = value;
+}
+
+void ui_headerbar_args_set_vexpand(UiHeaderbarArgs *args, UiBool value) {
+    args->vexpand = value;
+}
+
+void ui_headerbar_args_set_hfill(UiHeaderbarArgs *args, UiBool value) {
+    args->hfill = value;
+}
+
+void ui_headerbar_args_set_vfill(UiHeaderbarArgs *args, UiBool value) {
+    args->vfill = value;
+}
+
+void ui_headerbar_args_set_override_defaults(UiHeaderbarArgs *args, UiBool value) {
+    args->override_defaults = value;
+}
+
+void ui_headerbar_args_set_margin(UiHeaderbarArgs *args, int value) {
+    args->margin = value;
+}
+
+void ui_headerbar_args_set_margin_left(UiHeaderbarArgs *args, int value) {
+    args->margin_left = value;
+}
+
+void ui_headerbar_args_set_margin_right(UiHeaderbarArgs *args, int value) {
+    args->margin_right = value;
+}
+
+void ui_headerbar_args_set_margin_top(UiHeaderbarArgs *args, int value) {
+    args->margin_top = value;
+}
+
+void ui_headerbar_args_set_margin_bottom(UiHeaderbarArgs *args, int value) {
+    args->margin_bottom = value;
+}
+
+void ui_headerbar_args_set_colspan(UiHeaderbarArgs *args, int colspan) {
+    args->colspan = colspan;
+}
+
+void ui_headerbar_args_set_rowspan(UiHeaderbarArgs *args, int rowspan) {
+    args->rowspan = rowspan;
+}
+
+void ui_headerbar_args_set_name(UiHeaderbarArgs *args, const char *name) {
+    args->name = strdup(name);
+}
+
+void ui_headerbar_args_set_style_class(UiHeaderbarArgs *args, const char *classname) {
+    args->style_class = strdup(classname);
+}
+
+void ui_headerbar_args_set_showtitle(UiHeaderbarArgs *args, UiBool value) {
+    args->showtitle = value;
+}
+
+void ui_headerbar_args_set_showwindowbuttons(UiHeaderbarArgs *args, UiBool value) {
+    args->showwindowbuttons = value;
+}
+
+void ui_headerbar_args_set_alternative(UiHeaderbarArgs *args, UiHeaderbarAlternative alt) {
+    args->alternative = alt;
+}
+
+void ui_headerbar_args_set_alt_spacing(UiHeaderbarArgs *args, int spacing) {
+    args->alt_spacing = spacing;
+}
+
+void ui_headerbar_args_free(UiHeaderbarArgs *args) {
+    free((void*)args->name);
+    free((void*)args->style_class);
+    free(args);
+}
+
+
+
 /* ---------------------------- UiMenuItemArgs ---------------------------- */
 
 UiMenuItemArgs* ui_menuitem_args_new(void) {