An obvious followup question is why even have this setting if it does not work? I excpect the option “Global Styles: Selected text colour” to mean "globally set colour of selected text ".

Whit NPP closed select the folder in Explorer than drag and drop it on the NPP shortcut (e.g. the one your Desktop), it should open all files in the “old way”

Not supported by Notepad++. The TextFX plugin has an Insert Ruler function. However, it inserts a ruler as text in your file.

Hello Claudia, Thank you for looking into it and for the detailed explanation. I appreciate it. Good night. :)

Select Style Configurator... in the Settings menu, select e.g. HTML in the Language list, the Style list will show the descriptions of the items that are colored. Select one of these descriptions to show the specific color and font style for that item. Notepad++ does not indicate errors in source code natively. Maybe there’s a dedicated plugin with this functionality but I don’t know of any. You could Google for a HTML and CSS Validator.

Convenient? Maybe. Wise? Probably not. When any change to a third-party library gets automatically integrated into the this project, the project also automatically inherits the libraries (new/unknown) issues e.g. none backwards compatible changes in its interface. IMO a controlled/managed update of third-party libraries/tools with regression tests/checks is preferred.