If Notepad Plus Plus refuses to show HTML or any code markup colors

You may have activated HTML as the language of the file you opened in Notepad++, you may even have saved your file with an html extension, only to discover that the editor refuses to use all those convenient HTML colors that would let you easily locate the code sections and lines in your document.

You don’t need to change language or highlight modes, and of course not themes…

To solve your problem just go to Notepad’s Style Configurator and clear (uncheck) the option “Enable global foreground color”.