Which Windows Explorer replacements have this feature: takes over folder open operations?

Question

There have been at least a few threads about Explorer replacements, aka alternative file managers, here on Superuser. The go-to thread seems to be this one: https://superuser.com/q/90/60860

But what I would like to have is a narrower subset of these available choices with the feature that I indicated in the title: that is, I am interested only in such Explorer replacements which integrate themselves with Windows and do not need to be opened or launched. In other words, if I double click a folder, then the folder would be opened by this Explorer replacement. This is in contrast to how many alternative file managers are, which do not take over from Explorer. I did some searching, and user fluxtendu linked a cool wikipedia page containing feature comparisons between file managers, but unfortunately it doesn't mention the feature that I'm looking for.

I am already aware from personal experience of one that fulfills this criterion: Explorer++. And I was told by afrazier that Directory Opus and explorer2 also do this. What other options exist?

And of course, I would also appreciate recommendations. I guess I wasn't totally happy with Explorer++, which is why I want to try out others.

Answer 1

The problem is that Windows Explorer also provides the whole shell for Windows. So when you click that Folder icon, you're most likely already using Explorer. It just starts another process (or window).

You might want to look into shell replacements.

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Update

Ok, let me go into a little bit more detail about my understanding of things.

How the whole system works

Let's start with my desktop.
My desktop is drawn by the shell. The shell is provided by the initial explorer.exe process that runs when Windows starts. If I have a folder on my desktop:

I can double-click it to open it:

This created a new explorer.exe process which is now displaying the window that shows the contents of my folder. But there are many way the same window could have been opened.

So why did Windows to decide to use explorer.exe to display that folder?
Well, as I said, the desktop is already an explorer.exe process. So it will simply use ShellExecuteEx() to let the shell decide what to do with it. The shell will then create a new explorer.exe instance (because it is hard-wired to do so to my knowledge).

So what you can do, is not use explorer.exe to provide your shell (as you already seem to do). You can simply provide an alternative application in the registry under:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell

But nobody is stopping that new shell from calling ShellExecuteEx(), which would, again, invoke the default shell and, thus, explorer.exe!

So, what now?

So if you really want to replace Windows Explorer, replace the file explorer.exe. Because, in the end, every program could still try to execute C:\Windows\explorer.exe directly and then you have the same old Explorer again.

But, please keep in mind, I have never attempted to replace explorer.exe on a system, so I don't know if that would even be possible and/or stable to use.

How does application XYZ do it?

There are several applications that simply plug into Explorer, like QTTabBar. Maybe Explorer++ works the same way. This way you don't need to touch anything as your modification is always loaded into new explorer.exe processes. Going into detail about that process would take a whole new answer.

What about the File-Open dialog?

This is a whole new set of problems. The File Save and File Open dialogs are part of the Common Dialogs Library. Trying to replace those is hard to imagine. Pretty much the same can be said about those as I said about explorer.exe. But this would be far more scary.