Single click to open an item not working

The topic says it all. I want to hover over an item in a lister to select it, and I want to open the item with one click. Since my recent upgrade to the latest version, even though this item is selected in Preferences, it no longer works as expected.
Thank you.

Is it only images that it doesn't work on, or everything?

It appears to be everything. Mostly I'm working with text files rather than images.

Actually, as it turns out, it seems to be working fine on a network drive but not on my local drives. I don't know why it would be intermittent-sometimes working fine but other times not.

You've probably configured your local drives to use Power Mode instead of Details Mode. The single-click option doesn't affect Power Mode (which exists to let you do other things with the mouse buttons).

You can see which mode you're currently in by seeing what's selected in the View menu at the top of the window by default.

Preferences / Folders / Folder Formats will most likely be where the mode switch on local drives is coming from.

Now you're probably getting to the nub of what my real question is. Last week I was wondering if Power Mode had something to do with this, but I couldn't figure out how to get out of Power Mode if I was in it. I would be happy to follow your suggestion to check the View menu, but I don't seem to have a View menu. Nor do I see a mode switch in Preferences / Folders / Folder Formats, but maybe I just don't know what I'm looking for. But I think (I hope) that we are on the right track.
Thanks.

The View menu should be here if you're using the default toolbars:

If you're using custom toolbars or have deleted it then you can usually get to it by right-clicking the file display background, unless you've edited that menu as well.

Okay, now I see it. But I'm still missing how to turn off Power Mode for the folders that seem to have it enabled.

Never mind. I got it. Thanks again.