Meanwhile, is it intended that the Now Playing List (and Column Browser) overrides no longer work?
Also the "search" placeholder text in the search box no longer uses the skin color.
the column browser should apply the filter panel override for the next update. The last update should have correctly set the "search" text which should have only not applied the override when in the caption bar.
However i am not sure for the Now Playing list what override you are refering to, Can you give me an example of a skin where this override is being used and do you know the element name? (I have looked in the code and cant find anything but it might be done in a non-obvious way for me to find easily)
edit:
found the Now Playing list. I will include it in the next update
I'm not sure if this relates to psychoadept's comment and Steven's fix. And understand that my comment is coming from the standpoint of I really don't know what I'm doing when working with skins. If ever there was a trial and error guy, that's me. I've taken hiccup's Jistme on the Outlook skin (xml) and have been trying to add alternating bars of color in the Track Details view of the Main Panel. For whatever reason, the bars are extending to the Column Browser. And what I'd like in the Column browser is just a background color without the bars.
I'm getting close, but I'm finding that v3 exhibits different results than v2.5.
This is 2.5:

And this is 3.x:

In the 2.5 version note the blank space under "2014" and under "A-Z." And in the 3.x version there are bars in those spaces. This is the same skin that shows differently in the two versions of MB.
So as an aside, what element do I need to change in order to have a plain solid background in the Column Browser? At this point I'd be very content to have it working as I want in 2.5.