Deleting a project should remove portlets depending on that project

Certain portlets, like the project stats portlet, depend on the existence of a particular project to run. If that project is deleted, the portlet complains with (caught) exceptions in the log:

2003-12-05 09:36:01,953 ERROR [velocity] ASTMethod.execute() : exception from introspection : java.lang.NullPointerException
[ERROR] ServletValueStack - -METHOD: "hasProjectPermission", exception:
<java.lang.NullPointerException>java.lang.NullPointerException
at webwork.util.ValueStack.findMethod(ValueStack.java:743)
at webwork.util.ValueStack.findValue(ValueStack.java:382)
at webwork.expr.Parser.findValue(Parser.java:332)
at webwork.expr.Parser.comparative_expression(Parser.java:224)
at webwork.expr.Parser.logical_and_expression(Parser.java:173)
at webwork.expr.Parser.test(Parser.java:143)
at webwork.util.ValueStack.test(ValueStack.java:131)
at webwork.view.taglib.IfTag.doStartTag(IfTag.java:38)
at org.apache.jsp.projectstats_jsp._jspx_meth_webwork_if_0(projectstats_jsp.java:137)
at org.apache.jsp.projectstats_jsp._jspx_meth_webwork_property_0(projectstats_jsp.java:111)
at org.apache.jsp.projectstats_jsp._jspService(projectstats_jsp.java:79)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:137)

JIRA ought to delete these stats portlets when a dependent project is deleted, or at least print an intelligent message.