When I do (for example) /window -a "Status Window" or /window -a "#channel" those windows are activated. But when I do same with DCC chat windows (/window -a "=Nick") I get error message "* /window: invalid parameters". If I drop quotation marks, it works fine. This means that quotation marks don't work with DCC chat windows.
Of course there's a way around it...
var %w = <name of the window>
if ($chr(32) isin %w) window -a $+(",%w,")
else window -a %w
...but I think quotation marks should work with any window.