Hi Mike,The fontFamily and fontSize CSS properties for the InfoWindowLabel are being overwritten at run-time by UIManager.as:
var cssStyleDeclarationInfoWindowLabel:CSSStyleDeclaration = topLevelStyleManager.getStyleDeclaration("com.esri.ags.components.supportClasses.InfoWindowLabel");
cssStyleDeclarationInfoWindowLabel.setStyle("fontSize", fontSize);
cssStyleDeclarationInfoWindowLabel.setStyle("fontFamily", fontName);
topLevelStyleManager.setStyleDeclaration("com.esri.ags.components.supportClasses.InfoWindowLabel", cssStyleDeclarationInfoWindowLabel, false);
You could try creating a CSS style in defaults.css and setting the styleName property in your skin to the name of the style you created (I haven't tested to see whether this will override the fontSize/fontFamily declarations), or you could comment out these lines in UIManager.as.Please remember to use the "Vote Up" and "Mark as Answer" buttons if this post has been helpful to you.