If you can find a copy (it does not appear to be sold, it can be found by poking around a bit) of Visual Slickedit, it does a fair job.
Dariusz Piatkowski created VSE_ModernTheme_0-6.zip, (on hobbes) which allows VSE to recognize many more OS/2 specific calls for highlighting....
Thanks Andy for the mention!
Yeah, Martin with all the various nuances that our VERY old version of VSE exhibits, it is the only editor I use.
Uber-customizable, you get to create Projects where each one can have it's own definition of Toolsets, so I have VACPP4 project, and GCC projects, and yet the same IDE buttons work as you would functionally expect them to because I can define what each button actually executes (along with the parameters, etc.).
My VSE_ModernTheme package was an attempt to bring a little bit of font/colour scheme refresh. As I started to dig into the GCC header file scans I paused because I actually started to think that the VACPP and GCC stuff should not be mixed, and since VSE provides for a way to differentiate these, and that includes actually loading Project specific configurations, I could actually define separate schemes, etc.
Ultimately, the challange is that our VSE has gone DEAD a long time ago. Now, I wil say this (to second Andy's remark): look around (not even hard digging that we are talking about here) and you'll find it!