Prevents clipping of filter tooltip

(ported from 3.x #456)

Author: jeff-phillips-18

src/filters/filter-fields.html

@@ -1,7 +1,8 @@
 <div class="filter-pf filter-fields">
   <div class="input-group form-group">
     <div uib-dropdown class="input-group-btn">
-      <button uib-dropdown-toggle type="button" class="btn btn-default filter-fields" uib-tooltip="Filter by" tooltip-placement="top">
+      <button uib-dropdown-toggle type="button" class="btn btn-default filter-fields"
+              uib-tooltip="Filter by" tooltip-placement="top" tooltip-append-to-body="true">
         {{$ctrl.currentField.title}}
         <span class="caret"></span>
       </button>