Apple X11 Update
You can download Apple X11 Update 2.6.5 for Mac from our software library for free. The software lies within System Tools, more precisely System Optimization. The actual developer of this free software for Mac is Apple, Inc.
From the developer:
Apple X11 Update is recommended for all X11 users and solves an issue that may cause X11 applications to become unresponsive.
You may want to check out more Mac applications, such as OpenMenu X, Air Mic or Dock Delight, which might be similar to Apple X11 Update.