The feature.xml is missing these required import
statements.
<import plugin="org.eclipse.ui.ide"/>
<import plugin="org.eclipse.jface.text"/>
<import plugin="org.eclipse.ui.workbench.texteditor"/>
<import plugin="org.eclipse.core.resources"/>
<import plugin="org.eclipse.ui.editors"/>
<import plugin="org.eclipse.core.runtime"/>
<import plugin="org.eclipse.ui"/>
Patched Feature.xml