When I swipe to show desktop, I can't select or move icons

I used to love being able to swipe to show my desktop on my MacBook Pro (15" retina display) and move icons around. But I noticed recently that I'm no longer able to move icons around ! Now when I swipe to show desktop, it shows me the desktop but everything is frozen. Unclickable. If I do try to click on something, the cursor turns into a black upward facing arrow.

I tried going into System Preferences to play with the trackpad settings. Strangely enough, I found that when I unchecked the "Show desktop" option and then checked it again, it worked very briefly. But then a moment later it didn't work again.

Help! It's incredibly frustrating to not be able to use a function that is muscle memory for me at this point.