.widget-header
  %h3 Review Tags
.widget-content
  %fieldset
    = form_for proposal, url: event_staff_proposal_path(event, proposal), html: {role: 'form', remote: true} do |f|
      .form-group
        .tag-list
          = f.select :review_tags,
            options_for_select(event.review_tags, proposal.object.review_tags),
            {}, { class: 'multiselect review-tags', multiple: true }
          %button.pull-right.btn.btn-success{:type => "submit"} Update

.widget-header
  %h3 Review Tags
.widget-content
  %fieldset
    = form_for proposal, url: event_staff_proposal_path(event, proposal), html: {role: 'form', remote: true} do |f|
      .form-group
        .tag-list
          = f.select :review_tags,
            options_for_select(event.review_tags, proposal.object.review_tags),
            {}, { class: 'multiselect review-tags', multiple: true }
      .form-group
        %button.btn.btn-success.pull-right{:type => "submit"} Update

Move button to avoid collision with long tags list
Move button to avoid collision with long tags list