Impossible to set F11 on a MacBook

[brunzenstein]

As evidenced by the attached screenshot - all F keys may be set on the keybinding card except the F11
But I could edit and set the F11 within the ini.file
PS: how to mimic the middle-mouse-button on a MacBook without a mouse?
The expected to work "three finger click" cannot be set though.

[HanziQ]

F11 is usually bound to "Show desktop" in OS X, when I disabled that, I could bind F11 without any problems. Not a bug.

[brunzenstein]

F11 is usually bound to "Show desktop" in OS X, when I disabled that, I could bind F11 without any problems. Not a bug.

Thank you for the hint. One cannot see the wood for all the trees