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
Point result = new Point(buttonSize.x, Math.max(contentsSize.y,
                    buttonSize.y));
            return result;
        }
    }
    /**
     * Default DialogCellEditor style
     */
    private static final int defaultStyle = SWT.NONE;
    /**
     * Creates a new dialog cell editor with no control
     * @since 2.1
     */
    public DialogCellEditor() {
        setStyle(defaultStyle);
    }
    /**
     * Creates a new dialog cell editor parented under the given control.
     * The cell editor value is <code>null</code> initially, and has no 
     * validator.
     *
     * @param parent the parent control
     */
    protected DialogCellEditor(Composite parent) {
        this(parent, defaultStyle);
    }
    /**
     * Creates a new dialog cell editor parented under the given control.