@hdmi in my case I have also icons on the desktop, which would be a problem with full menu transparency.
On Win 7 with Classic Shell, this wasn't a problem. The menu was just opaque enough (see the icons below?):
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On Win 11 I have yet to find this kind of semi-opaqueness on my Open-Shell start menu. And I won't be using another start menu because I just like Open-Shell for that purpose.
BTW sorry for the question, but why bring back Win 10 taskbar on Win 11? I don't even know what ExplorerPatcher is, so...