Registry Issue: Can't Run Alt. Start-up Program From Win10/64 Shell

Hi! I created a program that creates a batch file to compile C modules into old computer executables using the cc65 compiler and have an issue: when I select an option added by the program, Win10/64 asks me how to open the file. The options given include Notepad++. I don't want that. I want to automatically use my program just this once every time I want to. Following are dumps from RegEdt32:
-------------------------
Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\.c]
"PerceivedType"="text"
@="cfile"
"Content Type"="text/plain"

[HKEY_CLASSES_ROOT\.c\DefaultIcon]
@="C:\\MyPrgs\\DOS\\TempC\\TempC.ico"

[HKEY_CLASSES_ROOT\.c\OpenWithProgids]
"VisualStudio.c.14.0"=""

[HKEY_CLASSES_ROOT\.c\OpenWithProgids\Shared]
@="Shared key to keep this from being removed with install/uninstall of side-by-side components."

[HKEY_CLASSES_ROOT\.c\PersistentHandler]
@="{5e941d80-bf96-11cd-b579-08002b30bfeb}"

[HKEY_CLASSES_ROOT\.c\ShellNew]
"Command"="\"D:\\Dev\\CBoost07b\\TempCMod1.exe\" \"%1\""
-------------------------------
Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\cfile]
@="C Source File"

[HKEY_CLASSES_ROOT\cfile\DefaultIcon]
@="C:\\WATCOM\\binnt\\viw.exe,2"

[HKEY_CLASSES_ROOT\cfile\shell]
@="open"

[HKEY_CLASSES_ROOT\cfile\shell\open]

[HKEY_CLASSES_ROOT\cfile\shell\open\command]
@="C:\\WATCOM\\binnt\\viw.exe %1"

[HKEY_CLASSES_ROOT\cfile\shell\open2]
@="Open in &Notepas"

[HKEY_CLASSES_ROOT\cfile\shell\open2\command]
@="C:\\notepas-win32\\notepas.exe \"%1\""

[HKEY_CLASSES_ROOT\cfile\shell\open3]
@="Open in &Notepad++"

[HKEY_CLASSES_ROOT\cfile\shell\open3\command]
@="C:\\Notepad++\\Notepad++.exe \"%1\""
---------------------------

 

Try holding shift and right clicking on the file and selecting open with.. browse for the file you want to use and select always use this file.

 

I have more information: this seems to occur only when a batch file is associated with a particular option. Also, for some reason, the particular entries referred don't appear in RegEdt32.