The reason for this, I expect, is the right-click option "Always on top". By right-clicking any gadget, and selecting "Always on top", it seems to also make the gadget resist the show desktop command... sometimes. This is the pattern that I can make out:
Press win-D once: Other windows disappear, sidebar gadgets remain visible.
Press again: Other windows return.
Press a third time: All windows and gadgets disappear.
Press a fourth time: Windows become visible, gadgets remain invisible.
Press win-G (which I discovered purely by accident): Sidebar gadgets return to visibility.
However, it seems that sometimes the gadgets survive the third step anyways.
If the "Always on top" option is not checked, then the gadgets behave as a normal window would.
Note that I am referring to the right-click option of each individual gadget, not the option in the gadget properties.
Source: http://social.msdn.microsoft.com/Forums/en-US/sidebargadfetdevelopment/thread/d40a3ee8-66f8-4804-a41f-e190d7b3a78f
I hope this helps!
Brett M,
Windows Outreach Team
Anytime I click the Show Desktop button at the bottom-right in Windows 7, it shows me the desktop, BUT my sidebar gadgets all disappear. They all re-appear as soon as I un-minimize anything on my taskbar. Rebooting doesn't change this behavior. Anyone heard of this glitch and know a fix for it?
If the problem isn't clear, here's more of a step-by-step of what's happening:
-I have a few Google Chrome windows up, let's say.
-I *hover* over the Show Desktop button, and it shows my desktop, and my sidebar gadgets are all there. No problem so far.
-I *click* on the Show Desktop button, and it shows the desktop, *and* the sidebar gadgets are suddenly gone, as if the sidebar has also been hidden in order to show the desktop.
-Let's say I click on the Start menu and open sound recorder...The sidebar gadgets re-appear at this point. Likewise if I restore one of the windows that's minimized on the taskbar.
Thanks for your time, everyone.

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