When right-clicking on an item in the tree and selecting delete, instead of the item being deleted, you get an error message:
"HTTP 405 - HTTP verb used to access this page is not allowed"
This problem can occur if the user has installed the IIS feature with all options ticked, including the "WebDAV Publishing" option - you can confirm this via Control Panel -> Programs And Features -> Turn Windows features on or off.
If you see Web Server (Internet Information Services) -> Common HTTP features -> WebDAV Publishing enabled, this is the likely cause.
To fix it either:
In some cases (normally only Windows Vista or Windows Server 2008) the DELETE verb may not be allowed, you can enable it by loading the Internet Information Services (IIS) Manager,
clicking on the site where Enterprise Tester exists (normally "Default Web Site"), then clicking on "Request Filtering".
On the Request Filtering page, switch to the "HTTP Verbs" tab - if you see that "DELETE" has "Allowed" set to False, this is the cause. Remove this entry or changing it to explicitly be allowed will fix the issue.
If the list is empty, sometimes added "DELETE" verb (all capitals) to the Allowed Verb list will fix the issue too.