Okay, I don't really know if this is connected to Classic Shell Explorer or the regular Windows 7 Explorer, but I don't want to deinstall Classic Shell just to check it when you probably know an easier way to verify this ;):
When the folder pane is open and you select a folder, it is highlighted in classical blue. When you now select a file inside that folder in the files pane it is highlighted blue and the former highlight of the folder turns to gray. This is fine! But now select the parent folder in the folder pane again and you will notice that while the selected folder is highlighted blue, the file highlight does not turn to gray but stays blue. This is prone to create problems because if you now press delete the complete folder will be deleted and not the selected file, although you might think it's the other way around.
KB2653385 (http://support.microsoft.com/kb/2653385) fixes the problem for Windows 7 SP1. Unfortunately, due to the unfortunate and poor way in which the Windows division is run now, the bug has cropped up again for Windows 8. Sigh as this did not happen in the old Microsoft.
I am experiencing the exact scenario described above. I had a sub-folder in my C:\work directory highlighted in the right pane, and C:\work was highlighted on the left pane. Both highlights were in classic blue. I hit the delete button while holding down the shift key. expecting only the sub-folder to be permanently deleted. What actually happened was all of the contents of my C:\Work directory was deleted, except for a few files that I had open.
THIS BUG CAN BE DANGEROUS! I have a screen shot of the "Double Highlight", but I can't upload this.