Using the newest version, when I set scheduler.config.mark_now = false; is this supposed to make the current day white instead of yellow?

I am using the flat skin with dhtmlxscheduler_units.js

Ahhh… I see how it scheduler.config.mark_now = false; works. Once I included dhtmlxscheduler_limit.js it turns on/off the red line – very nice.

How can I make the current day not show in yellow?

you can disable it with css style, check the example

That takes away the horizontal lines in the Units view. Is there something which can be done so the current day looks the same as the other days? So it is not highlighted in yellow?

it does not, as you can see on a demo the current date looks exactly the same as others.
The style should set the same background image as in other columns. Make sure that url to the image file is specified correctly. It should go to codebase/imgs_flat/databg.png from a scheduler package

Got it. I needed to specify the complete path to the image. It is working now. Thanks for pointing that out.