diff --git a/plugins/diopser/src/editor/button.rs b/plugins/diopser/src/editor/button.rs
index fbc74730..9384d113 100644
--- a/plugins/diopser/src/editor/button.rs
+++ b/plugins/diopser/src/editor/button.rs
@@ -1,3 +1,19 @@
+// Diopser: a phase rotation plugin
+// Copyright (C) 2021-2022 Robbert van der Helm
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
 use nih_plug_vizia::vizia::prelude::*;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::Arc;