Hello, I’m afraid it’s not possible. When IBM introduced colour display they failed to increase the display attribute area to implicitly define the colour attributes. They simply resued the existing green screen attributes. This is why you see column seperators when yellow is defined and . . . . underneath fields defined as TRQ. Sorry I can’t offer a solution. Regards Graham Street
It can’t be done in the way that you’d like. It is done either as a builtin function of the display device or the emulation software. In your example — BOSaNOVA — the emulation software has been written to make the drawing of those pixels optional.
The character attributes are still sent from the system. The emulation software just knows how to get around it when it renders the characters.