Bug 91266 [refactor/code completion] change method signature, code completion not useable
We can with CTRL-SPACE initalize code completion in the type selection of the change method signature. But if we then press enter to select the right type we just pointed out with code completion. The enter is consumed by the table below and the selected value in the code completion popup is ignored. So yes you can see what values there are but as far as i know you can't select them with the keyboard (mouse is possible)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/dialogs/TableTextCellEditor.java
import org.eclipse.swt.events.TraverseEvent;
import org.eclipse.swt.events.TraverseListener;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Text;
import org.eclipse.jface.contentassist.SubjectControlContentAssistant;
import org.eclipse.jface.util.Assert;
import org.eclipse.jface.viewers.CellEditor;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.TableViewer;
/**
 * <code>TableTextCellEditor</code> is a copy of TextCellEditor, with the
 * following changes:
 * 
 * <ul>
 * <li> modify events are sent out as the text is changed, and not only after
 * editing is done </li>
 * 
 * <li>a content assistant is supported</li>
 * 
 * <li>the <code>Control</code> from <code>getControl(Composite)</code>
 * does not notify registered FocusListeners. This is a workaround for bug
 * 58777. </li>
 * 
 * <li>the user can go to the next/previous row with up and down keys</li>
 * </ul>
 */
public class TableTextCellEditor extends CellEditor {