diff --git a/src/states.rs b/src/states.rs
index 9567f2d..503d4d2 100644
--- a/src/states.rs
+++ b/src/states.rs
@@ -295,7 +295,7 @@ impl States {
     pub fn future_state_change<'b>(
         &self,
         id: impl Into<Option<&'b str>>,
-    ) -> Result<impl Fn() -> Result<()>> {
+    ) -> Result<impl Fn() -> Result<()> + Clone + Send + Sync> {
         let state = id.into().map(|id| self.get_state(id)).transpose()?;
         let current_state = self.current_state.clone();
         let gui_handler = if self.control_top_gui {