drain remaining signals

hui/src/instance.rs

@@ -153,6 +153,9 @@ impl UiInstance {
     //first, drain and process the event queue
     self.input.update_state(&mut self.events);
 
+    //then, reset the (remaining) signals
+    self.signal.clear();
+
     //then, reset the draw commands
     std::mem::swap(&mut self.prev_draw_commands, &mut self.draw_commands);
     self.draw_commands.commands.clear();

hui/src/signal.rs

@@ -46,4 +46,10 @@ impl SignalStore {
       .drain(..)
       .map(|x| *x.downcast::<T>().unwrap()) //unchecked?
   }
+
+  /// Clear all signals
+  pub(crate) fn clear(&mut self) {
+    //XXX: should we clear the vecs instead?
+    self.sig.clear();
+  }
 }