Exclude Indexing of Files Without Extensions in Void Tools' Everything Search

Question

How can I prevent Everything Search Engine (a Windows file and folder search utility by Void Tools) from indexing files without extensions? In other words, I want the index to include only (1) files with extensions, and (2) all folders.

I found much written about how to search for extension-less files and even how to exclude them from a search, but nothing on how to stop Everything Search from indexing them in the first place.

The search below can exclude extension-less files:

!!file:*.*

The negative of this doesn't work when trying to exclude files from the index (Tools > Options > Indexes > Exclude > Exclude Files):

!file:*.* (doesn't work)

!!!file:*.* (also doesn't work)

I can search for and return a list of files without extensions like this:

ext:

But oddly, the negative does -NOT- work to exclude files without extensions from a search (also doesn't work for Indexes > Exclude Files):

!ext: (doesn't work in a file search; doesn't work in the "Exclude Files" criteria)

For now, my workaround is to set the search defaults (Tools > Options > General > Home > Search) to custom and the criteria to !!file:*.*. Extension-less files are still in the index, but excluded by default from a search.

Does anyone know how to actually exclude extension-less files from the index? I'm using version 1.4.1.935.