PreventDefaultOnly on Combination

[parsalotfy]

I want to prevent default Ctrl+F to make my own search and prevent default search of browser to appear.
When using this:

<FluentKeyCode PreventDefaultOnly="new[] {KeyCode.Ctrl, KeyCode.KeyF}" GlobalDocument=true/>

the F key will not work in Textboxes.
Does anyone know what am I missing here?

[Tyme-Bleyaert]

Have you tried adding IgnoreModifier=false ?