(This might be more appropriate to post in Discussions, but they are disabled here.)

The plugin panel has a dropdown list with Templates and ANSI-characters items.

When selecting the second item, ANSI-characters are displayed, which is logical and expected. When selecting the first item, CSS and HTML "folders" are displayed, which can be assumed from the item selected above, are Templates. However, this is not so (I will explain now). The context menu of this type of panel displays:

Insert
Add…
Edit…
Delete…
Duplicate…
—
Add from selection…
Add from clipboard…
—
Move up…
Move down…

When selecting items from the first part of the context menu, what appears are not the Templates creation windows, and not even the "folder" (Languages) creation windows for Templates, but snippets:

I suggest choosing one of the options to eliminate the ambiguity of the interface logic:

1. Rename the Edit Snippet, Snippet (i.e. Delete Snippet) and Snippets (i.e. Duplicate Snippet) windows to Edit Template, Delete Template and Duplicate Template or
2. Rename the Templates tab to Snippets, Snippet to Delete Snippet, and Snippets to Duplicate Snippet or
3. For the "folders" list, replace Add…, Edit…, Delete… and Duplicate… with Add Language, Edit Language, Delete Language and Duplicate Language (respectively) or change their behavior to the appropriate one or
4. Something else that will remove the interface confusion with the terms templates, snippets and the nature of snippet folders.

Code Snippets plug-in 1.7.1
Notepad++ v8.6.9 (64-bit)