I hope someone has a solution to this very annoying phenomenon!
Operating system: Win 7 enterprise 64-bit
Program related to the issue: Adobe acrobat professional extended 9.2
When I open a folder that contains PDFs, Pictures, Office documents files, movies... etc The preview pane at the right side of explorer window show the content of all the files EXCEPT the PDFs !!
Now If you will say the problem is the Adobe acrobat professional then guess what! I didn’t have this problem on the RC version of windows 7!!!
I tried installing Adobe acrobat reader. The preview pan didn’t show PDFs again!