Robert: You might be right. But in the InfoSymbolWindowSkin.mxml, there is no definition about the Key/Value columns. I only found them in the popUpRenderSkin.mxml. In my application, the pop-up contains 2 columns w/ equal width. Usually, Key (Attribute Name) is short but Value (Attribute value) is long. I want to reduce Key column width and meanwhile increase Value column width. Thanks.