Bug 36902 [preferences] IllegalArgumentException in JavaEditorHoverConfigurationBlock$3.keyReleased
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/JavaEditorHoverConfigurationBlock.java
public void widgetDefaultSelected(SelectionEvent e) {
			}
		});
		Composite stylesComposite= new Composite(hoverComposite, SWT.NONE);
		layout= new GridLayout();
		layout.marginHeight= 0;
		layout.marginWidth= 0;
		layout.numColumns= 2;
		stylesComposite.setLayout(layout);
		gd= new GridData(GridData.FILL_HORIZONTAL);
		gd.heightHint= convertHeightInCharsToPixels(parent, 10) + (2 * fHoverList.getBorderWidth());
		stylesComposite.setLayoutData(gd);
				
		fEnableField= new Button(stylesComposite, SWT.CHECK);
		fEnableField.setText(PreferencesMessages.getString("JavaEditorHoverConfigurationBlock.enabled")); 
		gd= new GridData(GridData.FILL_HORIZONTAL);
		gd.horizontalAlignment= GridData.BEGINNING;
		gd.horizontalSpan= 2;
		fEnableField.setLayoutData(gd);
		fEnableField.addSelectionListener(new SelectionListener() {
			public void widgetSelected(SelectionEvent e) {
				int i= fHoverList.getSelectionIndex();
				boolean state= fEnableField.getSelection();
				fModifierEditor.setEnabled(state);
				fHoverConfigs[i].fIsEnabled= state;
				handleModifierModified();
			}
			public void widgetDefaultSelected(SelectionEvent e) {
			}
		});