# HG changeset patch
# User wenzelm
# Date 1360530201 -3600
# Node ID 10062c40ddaa452a6cdec4c805bcf89f14cd4597
# Parent  70a4c11cd79eecec7cf08bdee862b75935527975
avoid crash (NPE) when properties are changed during prover startup (e.g. by font scaling);

diff -r 70a4c11cd79e -r 10062c40ddaa src/Pure/System/session.scala
--- a/src/Pure/System/session.scala	Thu Feb 07 13:20:05 2013 +0100
+++ b/src/Pure/System/session.scala	Sun Feb 10 22:03:21 2013 +0100
@@ -407,7 +407,7 @@
           reply(())
 
         case Session.Global_Options(options) if prover.isDefined =>
-          prover.get.options(options)
+          if (is_ready) prover.get.options(options)
 
         case Cancel_Execution if prover.isDefined =>
           prover.get.cancel_execution()