I have uploaded a new macro, highlight.vdm, at the Miscellaneous Macros section of my web page:
This macro allows you to quickly highlight words/strings in your text file.
You can use it to add color into a plain text file that normally does not use syntax highlight, or you can add more keywords to an existing syntax file.
Just mark a block (perhaps by double-clicking a word) and call the macro.
The selected word is added to a tmp syntax file and the syntax file is loaded and activated immediately.
You can select the keyword group by calling labels H1 to H4. This is most easily done by using snippets.
A snippets file highlight.snp is included with the package. You may want to copy it's contents to your default snippets file.