If you don’t mind the idea of creating some new commands (one-time-only) and executing TWO additional steps (every search), here is a workaround for Notepad++'s current inability to search in extensionless files.
Your workflow will be slightly modified:
Step 1: Run command “Rename *. to *.NOEXT” (defined below) on the Run menu to rename extensionless files to have extension “.NOEXT” (while you are editing any top-level file in the search tree that has a real extension)
Step 2: Run your desired search; add *.NOEXT to list of filespecs to search
Step 3: Run command “Rename *.NOEXT to *.” (defined below) on the Run menu to rename .NOEXT files back to being extensionless (again, while you are editing any top-level file in the search tree that has a real extension)
Details of command “Rename *. to *.NOEXT”:
One-time setup:
In Notepad++'s Run menu, choose Run…
Paste the following in “The Program to Run” box:
cmd /c cd $(CURRENT_DIRECTORY) & For /R %G in (*.) do REN "%G" "%~nG.NOEXT"
Press the Save button and name it something meaningful like “Rename *. to *.NOEXT”
After accepting the name via the OK button in the “Shortcut” window, press the Cancel button in the “Run…” window (yes, seems like the wrong thing to do).
Details of command “Rename *.NOEXT to *.”:
One-time setup:
In Notepad++'s Run menu, choose Run…
Paste the following in “The Program to Run” box:
cmd /c cd $(CURRENT_DIRECTORY) & For /R %G in (*.NOEXT) do REN "%G" "%~nG."
Press the Save button and name it something meaningful like “Rename *.NOEXT to *.”
After accepting the name via the OK button in the “Shortcut” window, press the Cancel button in the “Run…” window.
Thanks to this website for some helpful info on renaming files: http://ss64.com/nt/ren.html