In Firefox History, to reopen a previous page it takes a single click. But if your page has dropped off the menu and you need to Show All History and go down a few more lines, it requires double-click.
What is the logic that dictates, in general, whether a single or double click activates a task, and what is the operative logical difference between opening a page in the basic history menu, and a page in the expanded menu?
Is there a rule of thumb (besides memory of prior visits) that would lead a user to intuit whether one clock or two is required to effect any process?
I wouldn’t say there’s a ton of actual logic behind what requires one click vs two clicks, other than windows based things usually take two clicks while internet (ie links) based things usually only take one, but there’s certainly some overlap.
Having said that, all you have to do is watch you cursor. If it changes when you hover over the thing your going to click on, you only need to click one more time.
Now, I’ve never used (or even noticed) FF history, so I had to look for it. I see it’s a menu at the top, items in menus always require one click (for Windows anyways). But when you go to All History, it spawns a new window, similar to File Explorer. That’s going to require double clicking. More or less because single clicking wouldn’t work in that situation because single clicking to launch would break other features that relied on single clicking.
Generally, a click selects, and a double-click executes a shortcut on the selected item.
So, clicking on an icon selects it, so that you can then execute one of several commands on it (open, duplicate, move, etc.), and double-click executes the most common action, opening it.
With other UI elements, the metaphor has been stretched a bit thin, and different apps extend it in their own way.
It’s just an arbitrary choice made by the programmers. (I speak as a professional programmer for 30+ years.)
Microsoft issues some guidelines and standards for how applications should work under Windows, but probably most programmers haven’t even read them, so this kind of thing varies from one app to another.
Odd… I’m using Firefox, too, and for me, a double-click on the “Back” button just takes me back two pages (in other words, it’s just two single-clicks). To bring down the menu needs the right-click, which is usual for bringing up menus.
The pattern that I have noticed is this: a single click will either select something, or execute something. A double click will select it and execute it.