Bug 40772 [plan item] Smart tab on empty lines
When having the caret on an empty line, pressing tab cleans up the line and sets the caret it the right indentation column.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/WorkInProgressPreferencePage.java
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Group;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Text;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.preference.PreferencePage;
import org.eclipse.ui.IWorkbench;
import org.eclipse.ui.IWorkbenchPreferencePage;
import org.eclipse.ui.help.WorkbenchHelp;
import org.eclipse.ui.texteditor.ExtendedTextEditorPreferenceConstants;
import org.eclipse.ui.texteditor.quickdiff.QuickDiff;
import org.eclipse.ui.texteditor.quickdiff.ReferenceProviderDescriptor;
import org.eclipse.jdt.ui.PreferenceConstants;
import org.eclipse.jdt.internal.ui.JavaPlugin;
/**
 * Preference page for work in progress.
 */
public class 
WorkInProgressPreferencePage
	extends PreferencePage
	implements IWorkbenchPreferencePage {
	
	private static final String PREFIX= "WorkInProgress.";