Double-click on text file very, very slow to open

Starting a few months ago, when I double-click on a file (assume a text file (*.txt)) it takes 6-9 seconds for the new window to open with the program running.

Possible causes: upgrade to OPUS, WinDoze upgrade, other.

Internet search produces no relevant information ... lots of whining about slow boots but nothing related to my issue.

I run Win7-Pro x64.

Is the same true if you double-click the same file in Windows Explorer?