Can't move prop pitch control

[Gunfreak]

Trying to do a cold start but the little thing on the trottle won't move with the mouse and I have no idea what that is supposed to be in the control menu. 

[razo+r]

If you go to options and controls, you can filter by category. If you then pick one of the logical categories, you might find the controls for it.

Tip: It uses the same keys as for example the allied warbirds to change the RPM.

[Ala13_ManOWar]

Anyhow, it's useless unless you use the manual prop pitch, and unlike Bf109 where it can be useful at certain times (not many though), it's not recommended in any Fw190 to use manual prop pitch control.

[LeCuvier]

The buttons/switches on throttle and stick generally cannot be operated with the mouse. You need to bind these commands to buttons on your game controllers or use keybord commands.
While the flight manual says that you should put the propeller pitch control in manual mode for engine start, I agree with @Ala13_ManOWar that it's not necessary. And if you forget to switch back to Automatic mode at least after take-off, you will kill your engine.