I guess 1.0.10, right?
It may depend on how you changed the height...
If you used css it may be in either your custom.css or maybe you edited the source file (so it should be in index.css I think).
If you tweaked the js code it may be script.js where there is:
$('body').append('<div id="' + this.popup_id + '" class="popup_container"><div class="' + popup_class + '" style="max-height