How can I get rid of the annoying shadow around windows?

I unchecked "shadow" in desktop effects >> all effects ... but that did not eliminate those annoying shadows.

Check "Window decorations" under Appearance instead. Turn off the drop shadow and/or the window glow.

Thanks for pointing me in the right direction. I finally found it a bit deeper here: PC >> Configure your Desktop >> Look & Feel >> Appearance >> Windows >> Oxygen >> Shadows >> uncheck 'Active Window Glow' >> plus 'change window dropdown shadow' to size 5 vertical offset 5 >> Apply ... but then after much experimenting, I finally ended up changing the window decoration from "oxygen" to "web" ... and also changed the colors. Much cleaner, imho. While it's nice to have so many options, it is monumentally confusing and (imho) the defaults are waaaaaay overbuilt with waaaaaay too much glitz.