<%= form_tag(change_visibility_path, method: :post, html: { :class => "form-horizontal"}) do %>
  <%= hidden_field_tag :plan_id, plan_id %>
  <div class="control-group">
    <div class="controls checkbox-controls">
      <%= radio_button_tag :visibility, :institutional, :class => 'radio inline', :id => 'institutional' %>
      <%= label_tag :institutional, "With others from #{current_user.institution.full_name}", :class => 'radio-label' %><br/>
      <%= radio_button_tag :visibility, :public, :class => 'radio inline', :id => 'public' %>
      <%= label_tag :public, 'Publicly on the web', :class => 'radio-label' %><br/>
      <%= radio_button_tag :visibility, :private, :class => 'radio inline', :id => 'private', checked: true  %>
      <%= label_tag :private, '...Or keep it Private', :class => 'radio-label'%>
    </div>
  </div>
  <br/>
  <div>
  <%= submit_tag "Share", :class => 'btn btn-success', method: 'post' %>

  <%= button_tag 'Cancel', type: :reset, :class => 'btn btn-success', id: "cancel_action" %>
  </div>
<% end %>

<%= form_tag(change_visibility_path, method: :post, html: { :class => "form-horizontal"}) do %>
  <%= hidden_field_tag :plan_id, plan_id %>
  <div class="control-group">
    <div class="controls checkbox-controls">
      <%= radio_button_tag :visibility, :institutional, :class => 'radio inline', :id => 'institutional' %>
      <%= label_tag :institutional, "With others from #{current_user.institution.full_name}", :class => 'radio-label' %><br/>
      <%= radio_button_tag :visibility, :public, :class => 'radio inline', :id => 'public' %>
      <%= label_tag :public, 'Publicly on the web', :class => 'radio-label' %><br/>
      <%= radio_button_tag :visibility, :private, :class => 'radio inline', :id => 'private', checked: true  %>
      <%= label_tag :private, '...Or keep it Private', :class => 'radio-label'%>
    </div>
  </div>
  <br/>
  <div>
  <%= submit_tag "Share", :class => 'btn btn-success', method: 'post' %>
  </div>
<% end %>

Remove the extra Cancel button on the change visibility.
Remove the extra Cancel button on the change visibility.
