Permissions - Deny Deletions?

I want to set permissions to deny deletion of sub files and sub folders from a folder.

On my Windows 7 computer, I created a folder called "Test Permissions"
with a single file "test.txt" inside. Then I followed the chain below.

Properties > Security > Advanced > Change Permissions

> Select "Users (mark-PC\Users)"

> Edit > Deny the following three

(1) Create files/write data
(2) Create folders/append data
(3) Delete subfolders and files

The first two were in fact denied. Inside the "Test Permissions" folder,
I could not create folders, could not create files, and could not modify
files (test.txt).

However, (3) was not denied. I could in fact delete "test.txt" just fine.
What gives?

 

OK! I figured it out. In addition to steps 1-3, one must perform step 4, which is to deny
"Delete" in addition to denying "Delete subfolders and files." Then "test.txt" can't
be deleted. The folder "Test Permissions" can't be deleted either.

P.S. What I had was supposed to work from my research and from
the link "Learn about access control and permissions," on the securities tab.
I had to experiment by doing everything.

 

OK! One last comment.
To require denying "delete" of the outer folder to deny deletion of sub-files/sub-folders isn't logical given the fact
that deletion of sub-files/sub-folders was already denied. This must be a Windows 7 bug. I don't think this happens
on Windows 10, because I watched a video, but maybe someone could check.