Comment 1 for bug 316461

In Classic mode Maximus will _not_ undecorate the windows, this is because it trys to adhere to the default Ubuntu preferences. However, when you switch back to netbook mode, Maximus should then start to undecorate windows again.

If this isn't the case, it would seem that some gconf options were altered. To force Maximus to undecorate windows, run gconf-editor and navigate to /apps/maximus on the left pane. Then make sure the "undecorate" option is checked (in the right pane).