Revert "Bug 578160 - MonitoringPreferencePage does not need to extend"

This reverts commit 5239c6eb52b1e4ec97582dedb6a6e609ad64415e.

Reason for revert: causes cce

Change-Id: I8704652b5dc0ceb1b76b1f1a95cabcef3143218f
Reviewed-on: https://git.eclipse.org/r/c/platform/eclipse.platform.ui/+/190411
Tested-by: Platform Bot <platform-bot@eclipse.org>
Tested-by: Andrey Loskutov <loskutov@gmx.de>
Reviewed-by: Andrey Loskutov <loskutov@gmx.de>
diff --git a/bundles/org.eclipse.ui.monitoring/src/org/eclipse/ui/internal/monitoring/preferences/MonitoringPreferencePage.java b/bundles/org.eclipse.ui.monitoring/src/org/eclipse/ui/internal/monitoring/preferences/MonitoringPreferencePage.java
index a8245c1..77a762f 100644
--- a/bundles/org.eclipse.ui.monitoring/src/org/eclipse/ui/internal/monitoring/preferences/MonitoringPreferencePage.java
+++ b/bundles/org.eclipse.ui.monitoring/src/org/eclipse/ui/internal/monitoring/preferences/MonitoringPreferencePage.java
@@ -31,13 +31,16 @@
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Label;
+import org.eclipse.ui.IWorkbench;
+import org.eclipse.ui.IWorkbenchPreferencePage;
 import org.eclipse.ui.internal.monitoring.MonitoringPlugin;
 import org.eclipse.ui.monitoring.PreferenceConstants;
 
 /**
  * Preference page that allows user to toggle plug in settings from Eclipse preferences.
  */
-public class MonitoringPreferencePage extends FieldEditorPreferencePage {
+public class MonitoringPreferencePage extends FieldEditorPreferencePage
+		implements IWorkbenchPreferencePage {
 	private static final int HOUR_IN_MS = 3600000;
 	private BooleanFieldEditor monitoringEnabled;
 	private IntegerEditor longEventWarningThreshold;
@@ -96,7 +99,6 @@
 
 	public MonitoringPreferencePage() {
 		super(GRID);
-		setPreferenceStore(MonitoringPlugin.getPreferenceStore());
 		editors = new HashMap<>();
 	}
 
@@ -185,6 +187,10 @@
 		return label;
 	}
 
+	@Override
+	public void init(IWorkbench workbench) {
+		setPreferenceStore(MonitoringPlugin.getPreferenceStore());
+	}
 
 	@Override
 	public void propertyChange(PropertyChangeEvent event) {