Rendering issue in dashboard with user-defined filter

2012.08.29 15:18:23 ERROR rails  Can not render widget filter: 
ActionView::TemplateError (undefined method `selected_period?' for nil:NilClass) on line #137 of app/views/filters/_list.html.erb: 
134: measure = @filter_context.measure(snapshot, column.metric) 
135: %> 
136: <% if column.variation || column.metric.on_new_code? %> 
137: <%= format_variation(measure, :index => @filter_context.period_index, :style => 'light') -%> 
138: <% else %> 
139: <%= format_measure(measure) -%> 
140: <% if @filter_context.selected_period? %> 

    app/helpers/application_helper.rb:448:in `variation_value' 
    app/helpers/application_helper.rb:481:in `format_variation' 
    app/views/filters/_list.html.erb:137 
    org/jruby/RubyArray.java:1602:in `each' 
    org/jruby/RubyKernel.java:2064:in `send' 
    app/views/filters/_list.html.erb:131 
    org/jruby/RubyArray.java:1602:in `each' 
    app/views/filters/_list.html.erb:126 
    org/jruby/RubyKernel.java:2056:in `send' 
    compiled-template:8:in `_run_inline_1031195290_locals_dashboard_configuration_widget_widget_properties' 
    org/jruby/RubyKernel.java:2056:in `send' 
    app/helpers/dashboard_helper.rb:134:in `widget_body' 
    app/views/dashboard/_widget.html.erb:3 
    org/jruby/RubyKernel.java:2056:in `send' 
    app/views/dashboard/index.html.erb:16 
    org/jruby/RubyArray.java:1602:in `each' 
    app/views/dashboard/index.html.erb:12 
    org/jruby/RubyRange.java:407:in `each' 
    app/views/dashboard/index.html.erb:6 
    org/jruby/RubyKernel.java:2056:in `send' 
    org/jruby/RubyKernel.java:2064:in `send' 
    org/jruby/RubyProc.java:268:in `call' 
    org/jruby/RubyProc.java:228:in `call' 
    file:/lib/jruby-rack-1.0.0.1.jar!/vendor/rack-1.2.1/rack/head.rb:9:in `call' 
    file:/lib/jruby-rack-1.0.0.1.jar!/vendor/rack-1.2.1/rack/methodoverride.rb:24:in `call' 
    file:/lib/jruby-rack-1.0.0.1.jar!/jruby/rack/session_store.rb:42:in `call' 
    file:/lib/jruby-rack-1.0.0.1.jar!/jruby/rack/session_store.rb:39:in `call' 
    file:/lib/jruby-rack-1.0.0.1.jar!/rack/adapter/rails.rb:36:in `serve_rails' 
    file:/lib/jruby-rack-1.0.0.1.jar!/rack/adapter/rails.rb:41:in `call' 
    file:/lib/jruby-rack-1.0.0.1.jar!/jruby/rack/rails.rb:185:in `call' 
    file:/lib/jruby-rack-1.0.0.1.jar!/rack/handler/servlet.rb:19:in `call'