Eclipse windowbuilder java 1.6 1.7

I have just installed WindowBuilder for Eclipse and java 1.7 JDK, but when I create a new JFrame in Eclipse, and try to open the "design-view" in WindowBuilder I get the following error: "Eclipse is running under 1.6, but the Java project has a 1.7 Java compliance level, so WindowBuilder will not be able to load classes from the project. Use a lower level of Java for the project, or run Eclipse using a newer Java version."I have just installed WindowBuilder for Eclipse