Restrict bell events to the proper window. (#6012)

* Restrict bell events to the proper window.

As per the comment in mod.rs, bell events are sent to
all windows; not just the window containing the pane
which generated the event.

To prevent each bell ringing multiple times, the window
event handler must check if it has the pane, and ignore
the bell event if it doesn't.

This fixes bug #5985

Co-authored-by: Sean Estabrooks <sean.estabrooks@eztux.com>

wezterm-gui/src/termwindow/mod.rs

@@ -1223,6 +1223,10 @@ impl TermWindow {
                     alert: Alert::Bell,
                     pane_id,
                 } => {
+                    if !self.window_contains_pane(pane_id) {
+                        return Ok(());
+                    }
+
                     match self.config.audible_bell {
                         AudibleBell::SystemBeep => {
                             Connection::get().expect("on main thread").beep();
@@ -1878,20 +1882,23 @@ impl TermWindow {
         self.update_title_impl();
     }
 
-    fn emit_user_var_event(&mut self, pane_id: PaneId, name: String, value: String) {
+    fn window_contains_pane(&mut self, pane_id: PaneId) -> bool {
         let mux = Mux::get();
 
         let (_domain, window_id, _tab_id) = match mux.resolve_pane_id(pane_id) {
             Some(tuple) => tuple,
-            None => return,
+            None => return false,
         };
 
-        // We only want to emit the event for the window which contains
-        // this pane.
-        if window_id != self.mux_window_id {
+        return window_id == self.mux_window_id;
+    }
+
+    fn emit_user_var_event(&mut self, pane_id: PaneId, name: String, value: String) {
+        if !self.window_contains_pane(pane_id) {
             return;
         }
 
+        let mux = Mux::get();
         let window = GuiWin::new(self);
         let pane = match mux.get_pane(pane_id) {
             Some(pane) => mux_lua::MuxPane(pane.pane_id()),