Freeze in loading screen when create Project using Enter key

When user create a new project using Enter key instead of mouse click on the submit button, it will cause the Project UI freeze in loading screen.

For example:

Steps to Reproduce the problem:

1. Go click on Create Project link in Project menu.
2. Select Bug Tracking template and use mouse to click Next button.
3. Please enter any name and tab to key field (all input using keyboard no mouse to hover to next field).
4. After enter Tab key to Project Lead field, please type a character/alphabet that contain in user directory. For example:
   
5. Then hit Enter key. You will get this behavior:
   
   Also, the following stack trace:

   2013-09-23 15:19:02,450 http-bio-8080-exec-9 ERROR admin 919x70x1 3armqy 0:0:0:0:0:0:0:1 /rest/project-templates/1.0/templates [common.error.jersey.ThrowableExceptionMapper] Uncaught exception thrown by REST service
   java.lang.NoClassDefFoundError: com/atlassian/jira/rest/api/util/ErrorCollection
   	at com.atlassian.jira.projecttemplates.rest.ProjectTemplatesResource.createProjectFromFormRequest(ProjectTemplatesResource.java:127)
   	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   ...
   Caused by: java.lang.ClassNotFoundException: com.atlassian.jira.rest.api.util.ErrorCollection
   	at org.apache.felix.framework.ModuleImpl.findClassOrResourceByDelegation(ModuleImpl.java:772)
   	at org.apache.felix.framework.ModuleImpl.access$200(ModuleImpl.java:73)
   	at org.apache.felix.framework.ModuleImpl$ModuleClassLoader.loadClass(ModuleImpl.java:1690)
   	at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
   

For more details step, please download the steps.mp4 video.

Finding

• The problem is not reproducible in JIRA 6.0.8.

Workaround

• Please use the mouse to click on the submit button when creating a Project.