download this file and put it in your extensions folder (eg ~/Library/Application Support/SuperCollider/Extensions/). recompile.
it also works with swingosc.

extServer6.sc (req. sc3.3 (updated to be in sync with current Server.makeWindow))

//–previous versions
extServer5.sc (req. sc3.3 (now with levelmeter key and fit 1024 screens))
extServer4.sc (req. sc3.3 (SCButton's boxColor_ was changed to backgound_))
extServer3.sc
extServer2.sc
extServer.sc
RedSkin.sc