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
new Object[] { newValue.toString() }));
                    }
                    fireApplyEditorValue();
                }
            }
        });
        setValueValid(true);
        return editor;
    }
    /* (non-Javadoc)
     * 
     * Override in order to remove the button's focus listener if the celleditor
     * is deactivating.
     * 
     * @see org.eclipse.jface.viewers.CellEditor#deactivate()
     */
    public void deactivate() {
    	if (button != null && !button.isDisposed()) {
    		button.removeFocusListener(getButtonFocusListener());
    	}
    	
		super.deactivate();
	}
	/* (non-Javadoc)
     * Method declared on CellEditor.
     */
    protected Object doGetValue() {
        return value;
    }
    /* (non-Javadoc)