You need to change the `sgml` keywords in `filetypes.html` to add a lower-case `doctype` to the list (tested, it works). Probably none of those tags should be required to be only upper-case, but it would require fixing the HTML lexer from Scintilla to change that.
Refer to the user manual for information about customizing filetypes if you haven't done it before. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/geany/geany/issues/1489#issuecomment-298947037
