Thanks everybody, but I have found out what is happening myself.

I use Sandboxie and the enabling of this extension plus blocking of tracking cookies does not stick when doing it within Sandboxie.

If I open Chrome unsandboxed, enable the extension and select blocking of tracking cookies, it does stick. When I close my browser and then reopen with Sandboxie, the selection is as I chose in the unsandboxed Chrome, completely unchanged. No more disabling on browser closure or changing my blocking tracking cookies to allowed. Life is sweet.

Well, waddaya know - pure magic eh ?.