When writing a declaration, definition or call to a function CB has knowledge of, it pops up a handy tool tip. It'd be really nice if you could "complete" that argument list. Right now the list dissapears as soon as you start filling in the parameters.
Use case 1:
Prototype: int function(Foo* foo, Bar* bar, const Wolf* wolf, const Goat* goat, const Cabbage* cabbage, time_t now);
You are defining function, you type
int function(
and the tooltip appears, a keypress drops the arg list in for you.
Use case 2:
You've defined function as above, and want to add a prototype for it. Again, once you type the ( CB shows a tool tip. A single keypress completes the prototype for you.
Use case 3:
You want to call function(foo, bar, now); when you type the ( up comes the tooltip. You hit complete and now all you need to do is delete the casts.
[Maybe you could make it so that shift+complete only inserts the parameter names]