.cdr file type missing from Open and Import window

I have Corel X5.  If I double click a .cdr file from the windows file browser (not from within Corel Draw) it opens the file in CorelDRAW.

But if I launch CorelDRAW and try to open the file I can not select the file because the list of file extensions in the Open dialog does not include .CDR so I can't even see the file because I can't select the .cdr extension.