It's not so easy to reproduce that though, but finally somthing has been found: When the minimized button(or even any non-client buttons... not fully tested) has been clicked, If the hooked window choosed to hide itself rather than do minimizing really, It may cause the GetCursor() returns NULL, rather than a valid cursor handle. After that, the cursor will disappear while being moved on any other windows(or all visible ones) and will appear again while sliding just on the desktop.
I thought the bug would appear only when the blur be activated, it's not. It exists at least in 'seven' and 'Vista areo orange' skin being armed.
It may be inconvenient to you to reproduce that yourself: You may install a software named Microsoft VirtualPC 2007 and then run it. Then run the TT. You can open a normal window, like Windows Explorer or Notepad or whatever you have thought, Then(To reproduce the bug, do as i say exactly as the following, especially don't click your mouse carelessly) Double-click the virtualPC's systray-icon to let the VirtualPC Consol to show. click the title-bar once or more(but never click another place, like its client-area or other window or desktop). You should see its menu bar(main-menu) flashed once. Then click its minimize-button rapidly. Then you can move the mouse on another window and try to see what happened... You have only 1/5 rate or less to see what the bug does to you...

The bug could be avoided by add the VirtualPC Consol to the Exclude Manager taken by TT. However when the bug activate, not all people that using the TT would think it due to the VirtualPC Consol. Another window may also use ShowWindow or SetWindowPos... It's better to close that bug fundamentally.