Bug 44861 [CellEditors] DialogCellEditor does not handle focusLost()
Make sure you have org.eclipse.ui.examples.propertysheet_2.1.0 and open any *.usr file. Select "Richard" from the outline view and select "eyecolor" from the properties view (notice the ... button). Now open the search dialog and notice the ... button is still there. If you select other text or combo properties, notice the editor has been deactivated.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/DialogCellEditor.java
* The cell editor value is <code>null</code> initially, and has no 
     * validator.
     *
     * @param parent the parent control
     * @param style the style bits
     * @since 2.1
     */
    protected DialogCellEditor(Composite parent, int style) {
        super(parent, style);
    }
    /**
     * Creates the button for this cell editor under the given parent control.
     * <p>
     * The default implementation of this framework method creates the button 
     * display on the right hand side of the dialog cell editor. Subclasses
     * may extend or reimplement.
     * </p>
     *
     * @param parent the parent control
     * @return the new button control
     */
    protected Button createButton(Composite parent) {
        Button result = new Button(parent, SWT.DOWN);
        result.setText("..."); 
        return result;
    }
    /**
     * Creates the controls used to show the value of this cell editor.
     * <p>
     * The default implementation of this framework method creates