Доработка. Синяя рамка для рекомендованной помехи.

scenes/button-flat/button-flat.tscn

@@ -57,6 +57,14 @@ offset_bottom = 20.0
 theme_override_styles/panel = SubResource("1")
 script = ExtResource("1_ui6sg")
 
+[node name="recommend" type="ReferenceRect" parent="."]
+visible = false
+z_as_relative = false
+layout_mode = 2
+border_color = Color(0, 0.549509, 0.921779, 1)
+border_width = 5.0
+editor_only = false
+
 [node name="back" type="Sprite2D" parent="."]
 material = SubResource("ShaderMaterial_hhdyc")
 scale = Vector2(20, 20)

scenes/button-flat/nine-patch-button.gd

@@ -4,10 +4,12 @@ extends PanelContainer
 
 func set_text(val: String): $button.set_text(val)
 func set_disabled(val: bool): disabled = val
+func set_rec_visible(val: bool): $recommend.visible = val
 func get_text(): return $button.get_text()
 func is_pressed(): return $button.is_pressed()
 func is_toggle_mode(): return $button.is_toggle_mode()
 
+
 var _pressed: = false
 
 @export var texture_state0: Texture2D = preload('res://data/кнопка-квадрат-0.png'):