Is it possible to configure the "back" button to go to the parent folder? I know that I can configure a double-click in the file pane to do this, but the back button is more consistent with Windows explorer, which I still use frequently on other computers.
You can configure any button to run any command you want. The toolbar editing tutorial is probably a good place to start.
I'm confused about what you're trying to do here, though. Opus has Back, Forward, Parent buttons in the same layout as Explorer and they all do the same things as the buttons in Explorer.
I left out one detail - I am using the "back" button on my mouse. The mouse is not configured to do anything special with that button (logitech mouse), but DOpus seems to be defauling the back action as a "go back", where Windows intreprets it as "go up".
I have figured out a way to usually accomplish what I want by increasing the "recent list". In many cases, just walking back up this list will go where I want. But sometimes I use the breadcrumbs to move somewhere and would like to go up from there.
Logitech back buttons run "back" by default, even in Explorer, at least all that I've used.
It sounds like your mouse configuration has overridden what the back button does, either in all apps or just in Explorer.
Which mouse drivers are you using?
The Logitech SetPoint drivers come with a control panel that lets you assign different meanings to buttons in different applications. If you are using them, what's the button set to do? Are there any "application overrides" (I think that's the name of them) on the buttons?