This add-on is a drop in replacement for the standard debug window in Vaadin. Showing the debug console in a separate browser window has several benefits: 1) More space available without covering any parts of the actual application (especially when using multiple screens). 2) Previous log messages are not lost when the browser is refreshed (does not work in Opera) 3) Does not interfere with e.g. scrolling on the application page In addition, the format enables adding new features without being restricted by the very limited default size of the built in debug window. Some planned features include filtering by a specific component, showing full stacktraces (only available in GWT dev mode) and clear separation of messages if there are multiple Vaadin applications on the same page. To use the add-on, just add the .jar to WEB-INF/lib and recompile your widgetset if using Vaadin plugin for Eclipse. Otherwise, you have to manually inherit org.vaadin.consolewindow.ConsoleWindowWidgetset in your widgetset. With a recompiled widgetset, just add ?debug (or &debug) to the URL to open the debug window. If no window is opened, there might be an issue with your browser blocking popup windows.