Win10 changed the rules somewhat, so some of the earlier skins won't color the explorer backgrounds as they did initially, but you can change it in WB.  Check this post and Reply #2, see if it helps:

https://forums.wincustomize.com/482144/page/1/#3670393

Also, some programs won't let you change the window background color.

I wouldn't think so.  More likely that the skin has specific colors or images defined for the parts you're trying to change via system colors.  It'll only use system colors if it can't use anything else.

Try this:

Load the Diamond skin that ships with WB.  Open an explorer window, it should be bright white.  In wb, do the "modify style" / "Change system colors".  Change "System Colour :Window" from 255/255/255 to say 180/180/180 and apply the skin.  The Explorer window should become darker.  (Don't forget to go back and change it back if you want to.    )

That way you'll at least know that "things are working right".

Oh, and I don't know what the status of Firefox/WB is right now.  Firefox's updates do seem to mess with things.

Have you rebooted since you installed WB?  If not, do so.

If you had a version of WB installed (including the trial) before the version you have installed now, did you uninstall the old version, reboot, install the new version, (and then reboot)?  If not, try uninstalling, rebooting, installing, rebooting.

Otherwise, it's probably time to start a ticket with support:

https://esupport.stardock.com/index.php?/Tickets/Submit

You can include a link to this thread if you like.  Also good to copy the information from the "About" section of Windowblinds and paste it into the text.

You should get an automated response almost immediately.  Don't reply to it or send any additional emails, wait for an email from a person - each time you send them an email it throws you back to the end of the line.

There are two new color settings in SkinStudio 10 to set the explorer background colors to what you want. However, before the version with those color settings came out the explorer background colors could only be changed by setting the Window Background color in SkinStudio. This however ruined the backround of many applications and some areas in Windows 10 itself.

Anyone who designed WB skins for Windows 10 before the new color settings were added need to go back and fix their skins, as I have already done.

As far as you current issue here is the resolve.

1.  Open the skin in SkinStudio 10 (latest version).

2. Go to the "Change skin colours" area and in the drop down box select "Show me the skin defined system colors".

3. Set the Window background color to 255, 255, 255, this will make sure that many applications look correct.

4. Move the slider at the bottom of the window and slide right until you see the "Explorer background (Win 10)" and the "Explorer folder bar background colour (Win 10)" colors. Change them to your desired background color(s). I do not recommend setting the background to a dark color as it will cause issues with reading text in some areas of Windows 10.

Do not change the other two Windows 10 color settings below those 2 items.

5. Click the apply button in the window, bottom middle and your changes should apply.

6. Before closing SkinStudio I would recommend creating a new .wba for backup.

Hope this helps.   

What Tom said is correct and how we that make windowBlinds set our skins.

However you can change the left and right sides of File Explore using WB Config. Open WindowBlinds. Click on Modify style. Go to Change system colors. Go down to "System Color ExplorerBackground and change color. and click "apply style to desktop". This will change the right side of File Explorer------- To change the Left side of File Explorer look for "System Color ExplorerFolderBarBaclground. Change color and again cilck "apply style to desktop". This only works for Win10 as Win 7/8 require an image and color change using SKS only. 

NOTE:  This color setting doen't not work for Diamond and Corporate and maybe other StarDock or older skins. I didn't check all of them. However I did check 3 of my skins, 2 of Tom's and Don's skins the the above worked.

Dave, I don't see any problem. Actually for anyone interested it gives a couple way to change the backgrounds.

Thing is and to much detail to explain. You would have to see by taking some skins apart why these changes won't work. WB cofig does work just not for a very few skins. Many The Diamond and corp skin were made a long time ago. Some things are missed and or locked for certain changes. If someone can't find another skin that's works for them I have to say they will never be happy. So many skin with different colors both pretty plain and designed. Most all many color changes can be made just using the WB Modify style settings. 

There is information here that some had no idea about and now know. All is good.

TY all for HELPING!

Answers below...

Reboot, yes, several times...

I installed the trial version yesterday, first time ever trying WB.

Yes, I hit Apply Changes every time...  What is interesting is... when I change the specific colors, the sample boxes above show those changes.

>Go to the "Change skin colours" area and in the drop down box select "Show me the skin defined system colors".

         OK, maybe this is the problem... I only see "Change System Colours".   Where does it say "Skin Colours"?   I also think the screen is not displaying everything, some of the screen seems below the screen bottom... or maybe to the right... can not minimize the WB screen and get scroll bars on right and bottom to be sure... I moved the screen over to my 30" display vs. the 24" main display, could see a bit more, does not seem anything is missing. 

> "Show me the skin defined system colors".

        Where is this???

Thank you for clarification.... I did think u meant IE, vs. File Explorer...   checked file explorer, same, no change in color...

I wont comment on the other issues, as there is obviously something bigger going on, I assume.. I will mention, I have messed with screen colors in Win10 themes for some time always getting a low contrast theme... I used to accomplish this in FireFox well with in there settings, you can pick colors, now that wont work either...

BTW, I like the idea of the yardsticks, something simple to trouble shoot this.  shall I open a service tix?  Are any of you with WB?  this is some of the best tech support I ever got !!!  TY

Seems WB will do exactly what I need, if I can just jump this hurdle..

I'm not certain that the trial will let you change the system colors and I can't seem to find anything on it one way or another.  That too would be something you could ask support.

I do want to emphasize what I mentioned in Reply 3 - in general a skin will only use a system color if nothing else is specified.  You won't be able to make a lot changes that way, that would require changing them through SkinStudio as Dave and LightStar have been talking about.  I don't want you to be under the impression that you'll be able to quickly and easily make a lot of changes to a skin using System Colors.

The steps: 

Maybe you should mention what skin or skins you are trying to change. On Win10 the 2 I mentioned won't even change using SKS (skinstudio)

Yee, yes..

At my age sometimes there are not enough options.

Tried many other of the skins that come preloaded with WB

same problem.... colors change in the little sample display window in WB, but not in the system... 

I sent email off referencing this thread, obviously, something I am missing...I will post what I learn, TY all for offering me assistance....

I'm hoping you sent your question to Stardock Support.

See below

I would suggest you send in a support ticket. You will receive an auto reply letting you know it was received. Do not send in another ticket as you will be put back on the bottom of the cue.

https://esupport.stardock.com/index.php?/Tickets/Submit

Oops. Just posted before I posted. Sorry about that.