removed option attribute from plugin.xml
diff --git a/examples/org.eclipse.compare.examples/plugin.xml b/examples/org.eclipse.compare.examples/plugin.xml
index a0b6211..9157dcc 100644
--- a/examples/org.eclipse.compare.examples/plugin.xml
+++ b/examples/org.eclipse.compare.examples/plugin.xml
@@ -18,7 +18,7 @@
       <import plugin="org.eclipse.core.resources"/>
       <import plugin="org.eclipse.compare"/>
       <import plugin="org.eclipse.jface.text"/>
-      <import plugin="org.eclipse.core.runtime.compatibility" optional="true"/>
+      <import plugin="org.eclipse.core.runtime.compatibility"/>
    </requires>
 
    <extension