Fix lock

src/guihandler/guihandler.rs

@@ -890,9 +890,9 @@ impl GuiHandler {
     }
 
     pub fn process_callbacks(&self) -> Result<()> {
-        mem::take(&mut *self.callback_list.lock().unwrap())
-            .into_iter()
-            .try_for_each(|callback| callback())
+        let callbacks = mem::take(&mut *self.callback_list.lock().unwrap());
+
+        callbacks.into_iter().try_for_each(|callback| callback())
     }
 
     fn render(