- introduce a `form_dialog` class on dialog gadget, so that we can apply
different styles.
- add a rule overriding the rule making "big" editors in bottom group so
that in dialog mode they are not so big.
- force the maximize class to apply its height as !important, because
the added selector being more specific, it has priority over the one
from maximize.

http://lesscss.org/less-preview/ has been used to compile .less in .css