Windows 7: Cannot Right Click on Desktop

Basically, I cannot right click on the desktop. ONLY the desktop. I can still right click in explorer, and the "Remove File Menu from Windows Explorer" in Group Policy is not configured. Everything is accessible through explorer, but the desktop context menu simply doesn't open.

My desktop is clear of icons because I disabled it before, and now I don't know of any method to re-enable it other than right-clicking.

There are no viruses or anything else malicious on the computer, and system restore is disabled, so I can't just revert.

Interestingly, when I go to 'Personalization' and select a new theme, everything, the context menu, the icons, the works, comes back. I can right click, and all the icons are visible on the screen, but the moment I close the 'Personalization' tab, it reverts back to normal. Thoughts?

PS: Another annoyance: My taskbar is vertical. Vertical-left, if that matters. And the locked-custom-toolbar-partial-icon glitch is bugging me. (Basically, if I create a toolbar, and locate it near the start orb, and shrink it so that only the title and the drop-down arrow are showing, upon locking, the first bit of the first icon sticks out, due to the disappearance of the 'grab handles') The only workaround I found was for horizontal taskbars, i.e. unlocking the taskbar, moving it vertical, shrinking the toolbar as much as possible, the moving the taskbar back and locking it. But this doesn't work the other way-around.

And I want the toolbar near the start orb, not near the notification area, so default positioning isn't an option.

Cheers.