Why does F4 select my capital?

[SlyFrog]

I am supposed to be able to create unit groups with my F1 through F8 keys. However, for some mysterious reason, the F4 key is stuck on selecting my capital city, even after I try to bind a group to it.

I have checked the bindings in the hotkey options, and it says F4 is bound to nothing. Why is it selecting my capital?

[solo]

Because it happens to me, too! Luckily, there are plenty of other keys that work okay.

[wilebill]

Well, yet another undocumented keyboard feature; and a useful one too! Thank you!

In return, note that "c" will select the nearest city ... usually. Press c again will unselect the current city, then "cc" in quick succession will skip to the next city. Is there a quicker way to skip from city to city?