plugin.xml

<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.4"?>
<plugin>

   <extension
         id="frege-ide.fregeBuilder"
         name="Frege Project Builder"
         point="org.eclipse.core.resources.builders">
      <builder
            hasNature="true">
         <run
               class="frege.ide.builder.Builder">
         </run>
      </builder>
   </extension>
   <extension
         id="frege-ide.fregeNature"
         name="Frege Project Nature"
         point="org.eclipse.core.resources.natures">
      <runtime>
         <run
               class="frege.ide.builder.FregeNature">
         </run>
      </runtime>
      <builder
            id="frege-ide.fregeBuilder">
      </builder>
   </extension>
   <extension
         point="org.eclipse.ui.commands">
      <category
            name="Frege Project Nature commands"
            id="frege-ide.fregeNature.category">
      </category>
      <command
            name="Add/RemoveFrege Project Nature"
            defaultHandler="frege.ide.builder.AddRemoveFregeNatureHandler"
            categoryId="frege-ide.fregeNature.category"
            id="frege-ide.addRemoveFregeNature">
      </command>
   </extension>
   <extension
         point="org.eclipse.ui.menus">
      <menuContribution
            locationURI="popup:org.eclipse.jdt.ui.PackageExplorer?after=additions">
         <command
               commandId="frege-ide.addRemoveFregeNature"
               label="Toggle Frege Builder"
               style="push">
            <visibleWhen
                  checkEnabled="true" />
         </command>
      </menuContribution>
   </extension>
   <extension
         id="xmlProblem"
         name="XML Problem"
         point="org.eclipse.core.resources.markers">
      <super
            type="org.eclipse.core.resources.problemmarker">
      </super>
      <persistent
            value="true">
      </persistent>
   </extension>
   <extension
         point="org.eclipse.ui.commands">
   </extension>

</plugin>