pdarg is absolutely correct.
 
MIDI Track Background colors worked fine, just like Audio Track Background colors,  in X1 and X2.
X3 took away the ability to set default-per-track clip background colors (both audio and midi).
 
However, in X3, you can select existing clips of any type, and override the default background colors hard-coded in X3.

Yes, you can indeed take this approach - but as I stated above, it takes A LOT of work to get something we had by default in X1 and X2.
 
I put in an official feature request to Cakewalk. Maybe we'll see it in X3c?

Hi Guys, This is the first thing I noticed in X3, very annoying.
Would be great if we could get this working again as it was in X2.
In the Track view - If you choose the option not to show clip content then you will get some colours, not sure where those colours are defined though as I haven't looked into it that deep. But at the moment my clips have a dark background and the contents of the clips have the track colour.
The video about the new GUI says that track headers are now blue, mine are not , they are Black.
I also have white dotted lines around some of the clips, they weren't there in X2 either.

The plot thickens . . .

My clips headers are also black - just as they were in X2. But when I expand take lanes, the "pseudo-clip" in the main track DO have a blue header.
I kind of like it this way (normal clip black header, "fake" clip blue header)
 
I'm sure us folks who migrated settings from previous X2 installations are seeing lots of strange things color-wise. But the loss of clip background color control is particularly irksome.

I really haven't messed with MIDI clip colors, but, do they change per-track if you modify the track color itself?   
 

If you change the track colour the Clip contents follow that colour, not the Clip background.

GARYTHEBRIDGE
If you change the track colour the Clip contents follow that colour, not the Clip background.

Ahh... OK, thanks. 
 

Yes - but the MIDI track background is still dark gray/black.
If the X3 Track inspector offered an option to change both track foreground/backgrouhnd colors, we'd be all set.
X2 allowed; X3 does not.
Cakewalk - please change this back!

Ryan Munnis [Cakewalk]
 It was ultimately removed from the Preferences color option as being obsolete (i.e. having no affect) along with some other color preferences that were confusing customers.

Obsolete because nobody at home used these wonderful options?
 
MS removed the defrag graphics because it confused users. 
 
Who are these mystery confused customers/users?
 
And why do they get preferential veto power resulting in the sadness of the many who did not exclaim their happiness with the way it was?
 
The old squeaky wheel syndrome.   Don't figger why the other 3 wheels are not squeaking.
 
Just oil all of them to stop the whining. Even if the oil damages all of the wheels.