I wish I could remember who told me this, as I use it all the time now and would like to thank them. In any case I can pay it forward. If you use WindowBlinds and have SkinStudio, even the free version, you can change a setting, but you have to do it for each blind you want to use.
Select the blind in the Windowblinds Advanced Configuration screen and then click Edit in SkinStudio.
In the SkinStudio window, on the left, click Window Borders.
Now, somewhere in the list on the right should be an attribute Screen Edge Clip - Bottom. Select this attribute.
Now, near the bottom of the screen is a place to enter a Value. Enter a negative value (this is a number of pixels and will depend on the size of your docks). I use between -32 and -36.
Now I usually save the entire blind under a new name, but is up to you. Then you can apply the blind via the Tools menu in SkinStodio, and you're set.
Hope that helps!
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