File association

I have my Photoshop CS6 files (.psd) associated with Photoshop. Double clicking a .psd file opens it in Photoshop when not using Opus.
When I double-cclick a .psd file in Opus the Opus viewer opens.
Settings --> File type --> System File Types
has the .psd extention linked to PhotoShop. The link is set as the default and no alternative programs are listed.
How do I configure Opus to let Photoshop handle the .psd when double-clicked?

Additionally, but far less important, it would be nice if Opus displays the .psd in it's internal viewer pane when selected/single-clicked.

Thanks in advance.

Opus is trapping the double-click because of the Preferences / File Operations / Double-click on Files / Use internal picture viewer setting. You can turn this off, or override double-click for .PSD files only by editing the Left double-click event for the filetype.

Opus does (or should) show previews of .PSD files, but only if they have been saved with a preview image (the option for this in Photoshop Preferences is under File Handling).

Fixed.

Thanks Jon!

Dear Jon,
How do I do that?
So far, I go to Settings / Files types / psd
I can see that .psd are linked to open with Photoshop but when I Edit and go to the Command tab, I see that the left double click is not assigned. So, I double click on it, but in the Command list, I don't find 'Open'. So I don't know how to assign the function 'open with Photoshop'.
Thank you very much for your help!!

Easiest way is to copy the existing Open command.

Dear Jon,
Thank you but there is a problem because when I double click on a .psd file now it opens Photoshop but it doesn't open the file I clicked on...

Did you exactly copy the open command, e.g. with all quotes and especially the "%1" at the end ?
Can you share a screenshot of your dblclk edit action (as in Jon's post) ?

Very well done PassThePeas, that was my problem!! I missed the "%1"
Thank you very much for your help!!