Fixed: [Issue 213] Setting defaults in "Compiler" preference page does
not remove error messages

com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/PreferenceAndPropertyPage.java

diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/PreferenceAndPropertyPage.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/PreferenceAndPropertyPage.java
index c799f1c..3eaee35 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/PreferenceAndPropertyPage.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/preferences/pages/PreferenceAndPropertyPage.java
@@ -239,6 +239,7 @@
   @Override protected final void performDefaults() {
     preferenceBinder.applyDefaults();
     updateContents();
+    pageIsNowValid();
     super.performDefaults();
   }