Notepad++ 7.3.1 - Can Save File With Extension

I have latest version of Notepad++ - 7.3.1. When I save a text file, notepad++ does not add the extension "txt" and I need to add this manually. Previous versions did automatically add the extension. Is there something wrong with version 7.3.1 or am I doing something wrong?

 

Is the icon of the saved file a text icon or just a plain white box? do other txt files have this extension? This is in windows correct? Does the problem occur with the windows version of notepad?
One idea is that windows does not display the .txt extension by default. "Known" file types are not displayed. These would include the most common file extensions in windows.