make double sure that AWT/Swing antialiasing is enabled (see also http://www.jedit.org/users-guide/jvm-options.html and jdk/src/share/classes/sun/awt/SunToolkit.java);
--- a/src/Tools/jEdit/etc/settings Thu Oct 10 18:02:08 2013 +0200
+++ b/src/Tools/jEdit/etc/settings Fri Oct 11 12:06:26 2013 +0200
@@ -7,7 +7,7 @@
#JEDIT_JAVA_OPTIONS="-Xms128m -Xmx512m -Xss1m -Dactors.corePoolSize=4 -Dactors.enableForkJoin=false"
JEDIT_JAVA_OPTIONS="-Xms128m -Xmx1024m -Xss2m -Dactors.corePoolSize=4 -Dactors.enableForkJoin=false"
#JEDIT_JAVA_OPTIONS="-Xms512m -Xmx4096m -Xss8m -Dactors.corePoolSize=4 -Dactors.enableForkJoin=false"
-JEDIT_SYSTEM_OPTIONS="-Dapple.laf.useScreenMenuBar=true -Dapple.awt.application.name=Isabelle -Dscala.repl.no-threads=true"
+JEDIT_SYSTEM_OPTIONS="-Dawt.useSystemAAFontSettings=on -Dswing.aatext=true -Dapple.laf.useScreenMenuBar=true -Dapple.awt.application.name=Isabelle -Dscala.repl.no-threads=true"
ISABELLE_JEDIT_OPTIONS=""