simplify, correctly this time

Author: totaam

html5/js/Client.js

@@ -1661,13 +1661,13 @@ class XpraClient {
   on_mousedown(e, win) {
     this.mousedown_event = e;
     this.do_window_mouse_click(e, win, true);
-    return win == undefined;
+    return !win;
   }
 
   on_mouseup(e, win) {
     this.mouseup_event = e;
     this.do_window_mouse_click(e, win, false);
-    return win == undefined;
+    return !win;
   }
 
   on_mousemove(e, win) {
@@ -1677,7 +1677,7 @@ class XpraClient {
 
     // Ignore events when server is readonly, disconnected or if the event is not over the screen while in shadow mode
     if (this.server_readonly || !this.connected || (!win && this.server_is_shadow)) {
-      return win == undefined;
+      return !win;
     }
     const mouse = this.getMouse(e);
     const x = Math.round(mouse.x);
@@ -1696,7 +1696,7 @@ class XpraClient {
       e.preventDefault();
     }
     this.send([PACKET_TYPES.pointer_position, wid, coords, modifiers, buttons]);
-    return win == undefined;
+    return !win;
   }
 
   release_buttons(e, win) {