Explorer has a content sniffing feature so it tries to change to a view which it thinks is best suited for pictures, music, videos etc.
You could read this article:
How to set a folder view in Explorer for all folders – List, Details, Tiles, Small or Large Icons to understand how folder views work.
I believe there was a Registry key supported to disable folder contents sniffing too:
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Classes\Local Settings\Software\Microsoft\Windows\Shell\Bags\AllFolders\shell]
"FolderType"="NotSpecified"
But I haven't tested it, I am not even sure if it still works. Nor is Classic Shell responsible for anything that happens to your PC from Windows Registry tweaks. Do it at your own risk and restart Windows. You might want to do "Reset Folders" from Folder Options -> View tab and then do this Registry tweak.