... using WIN_FIXEDHEIGHT mode to limit the list height in wizard mode.

I had a solution using a negative width param value to specify a height limit,
but then I saw this code in ulist():
```
	if(mode&WIN_FIXEDHEIGHT) {
		height=api->list_height;
	}
```

something Deuce added for SyncTERM and I don't think I've ever used before.
It works.