If you are on the ground and your throttle is closed (fully back) the mixture is always on rich (fully back, too). You only can set the mixture to lean (fully forward) when the throttle lever is beyond a certain point toward forward. Test it (without engine running): Thottle full open (fully forward), mixture lean (fully forward). Slowly close throttle and you can see the mixture lever snap backwards at a certain point of the throttle lever movement...
...and no key, no mouse, no force, and no goddess will make it go forward again as long as the throttle is not moved forward first. Not a bug, by the way.
Artist
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Ceterum censeo the mixture axis should be supported in IL-2 1946' DeviceLink.
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