The docking window tabs work like a normal TabControl where there is a single ContentPresenter and that gets content swapped in for the currently selected tab. If that contain contains an enormous number of visuals, switching could be slower due to measure/arrange calls. There might be some things you can do to help a bit. Could you email our support address with a new simple sample project showing the slowness? In your email, please let us know exactly what version/build you are using, reference this thread, and be sure to rename the .zip file extension of what you send so it doesn't get spam blocked. Thanks!