Show Desktop delay

I have been using TLB for a few weeks on my W2K SP4 machine. A problem with the "Show Desktop" button has recently appeared. When the button is clicked with TLB loaded, there is sometimes a 5+ second delay to clean the desktop. Hitting it again quickly restores the desktop. Also, using the shortcut key (WindowsKey + D) results in quick clean of desktop. Finally, if I enable the standard Quicklaunch Bar and hit the Show Desktop button on that bar, the desktop clean is immediate.

So what is happening when this button (show desktop.scf) is involked via TLB that creates a problem??

Thanks,

Doug