TopDesk only tiles application windows, not dialog or tool windows. In most cases, if a window is in the Windows Taskbar it is an application window. If a window does not appear when tiled, it is not following the standard Windows guidelines for application windows.

Some applications may appear to have application windows when infact the window does not meet all the requirements for an application window. These applications typically exhibit custom behaviour, such as minimizing to the taskbar notification area when closed.