[OuNiS]

I checked it.

Reason: changing AA settings by pressing Shift+PgUp keys in a boat equiped with Radar Warning.

If your boat has Radar Warning system then when you increase AA by pressing Shift+PgUp Hydro bearing indicator will become blank. If you set AA to defualt value everything will back to normal.
If your boat doesn't have RW nothing happed!

I observe this after few hours of testing.

Thanks everybody for suggestions!