Windows 7 Ultimate x64 keeps thinking I'm still hovering over a taskbar program even though I'm no longer hovering over it, resulting in the hover colour and tooltip being displayed when it shouldn't.
In this screenshot, Chrome is my active window, yet iTunes remains lit up because I just hovered over it for a second, even though I've since moved the cursor and clicked on my Chrome window. This is unhelpful and distracting.

This bug is temporarily resolved by logging out, but it comes back after a while, not sure what causes it. This has happened to me on and off over several months. Few days ago I did a format and clean install, ran Windows Update completely, yet this is happening again.
Any ideas?