diff --git a/src/legacy/core_plugins/kibana/public/discover/__tests__/directives/field_chooser.js b/src/legacy/core_plugins/kibana/public/discover/__tests__/directives/field_chooser.js
index f74e145865475d..0489de0e8e1ead 100644
--- a/src/legacy/core_plugins/kibana/public/discover/__tests__/directives/field_chooser.js
+++ b/src/legacy/core_plugins/kibana/public/discover/__tests__/directives/field_chooser.js
@@ -138,7 +138,7 @@ describe('discover field chooser directives', function() {
 
   describe('Field listing', function() {
     it('should have Selected Fields, Fields and Popular Fields sections', function() {
-      const headers = $elem.find('.sidebar-list-header');
+      const headers = $elem.find('[data-test-subj="discover-sidebar-list-header"]');
       expect(headers.length).to.be(3);
     });
 
@@ -168,7 +168,9 @@ describe('discover field chooser directives', function() {
     it('should show the popular fields header if there are popular fields', function() {
       const section = getSections($elem);
       expect(section.popular.hasClass('ng-hide')).to.be(false);
-      expect(section.popular.find('li:not(.sidebar-list-header)').length).to.be.above(0);
+      expect(
+        section.popular.find('li:not([data-test-subj="discover-sidebar-list-header"])').length
+      ).to.be.above(0);
     });
 
     it('should not show the popular fields if there are not any', function() {
@@ -190,7 +192,9 @@ describe('discover field chooser directives', function() {
 
       $scope.$digest();
       expect(section.popular.hasClass('ng-hide')).to.be(true);
-      expect(section.popular.find('li:not(.sidebar-list-header)').length).to.be(0);
+      expect(
+        section.popular.find('li:not([data-test-subj="discover-sidebar-list-header"])').length
+      ).to.be(0);
     });
 
     it('should move the field into selected when it is added to the columns array', function() {
diff --git a/src/legacy/core_plugins/kibana/public/discover/np_ready/_discover.scss b/src/legacy/core_plugins/kibana/public/discover/np_ready/_discover.scss
index 764dd4d2280d62..07f598dce377d0 100644
--- a/src/legacy/core_plugins/kibana/public/discover/np_ready/_discover.scss
+++ b/src/legacy/core_plugins/kibana/public/discover/np_ready/_discover.scss
@@ -8,10 +8,6 @@
   flex-direction: column;
   height: 100%;
   overflow: hidden;
-
-  .sidebar-container {
-    background-color: transparent;
-  }
 }
 
 .dscApp__header {
diff --git a/src/legacy/core_plugins/kibana/public/discover/np_ready/angular/directives/_index.scss b/src/legacy/core_plugins/kibana/public/discover/np_ready/angular/directives/_index.scss
index 2bfc74ffa02790..d4b365547b40c5 100644
--- a/src/legacy/core_plugins/kibana/public/discover/np_ready/angular/directives/_index.scss
+++ b/src/legacy/core_plugins/kibana/public/discover/np_ready/angular/directives/_index.scss
@@ -1,3 +1,2 @@
 @import 'no_results';
 @import 'histogram';
-@import './collapsible_sidebar/index';
diff --git a/src/legacy/core_plugins/kibana/public/discover/np_ready/angular/directives/collapsible_sidebar/_collapsible_sidebar.scss b/src/legacy/core_plugins/kibana/public/discover/np_ready/angular/directives/collapsible_sidebar/_collapsible_sidebar.scss
deleted file mode 100644
index 5840ebc92578c7..00000000000000
--- a/src/legacy/core_plugins/kibana/public/discover/np_ready/angular/directives/collapsible_sidebar/_collapsible_sidebar.scss
+++ /dev/null
@@ -1,45 +0,0 @@
-// SASSTODO: Can't rename main class
-// because it's also the name of the angular directive
-.collapsible-sidebar {
-  .kbnCollapsibleSidebar__collapseButton {
-    position: absolute;
-    top: 0;
-    right: -21px;
-    cursor: pointer;
-    z-index: 1;
-  }
-
-  &.closed {
-    width: 0 !important;
-    border-right-width: 0;
-    border-left-width: 0;
-
-    > * {
-      visibility: hidden;
-    }
-
-    .kbnCollapsibleSidebar__collapseButton {
-      visibility: visible;
-
-      .chevron-cont:before {
-        content: '\F138';
-      }
-    }
-  }
-}
-
-.visEditor__content .collapsible-sidebar {
-  position: relative;
-}
-
-@include euiBreakpoint('xs', 's', 'm') {
-  .collapsible-sidebar {
-    &.closed {
-      display: none;
-    }
-
-    .kbnCollapsibleSidebar__collapseButton {
-      display: none;
-    }
-  }
-}
diff --git a/src/legacy/core_plugins/kibana/public/discover/np_ready/angular/directives/collapsible_sidebar/_index.scss b/src/legacy/core_plugins/kibana/public/discover/np_ready/angular/directives/collapsible_sidebar/_index.scss
index 1409920d11aa7f..c408c87501117f 100644
--- a/src/legacy/core_plugins/kibana/public/discover/np_ready/angular/directives/collapsible_sidebar/_index.scss
+++ b/src/legacy/core_plugins/kibana/public/discover/np_ready/angular/directives/collapsible_sidebar/_index.scss
@@ -1,2 +1 @@
 @import 'depth';
-@import 'collapsible_sidebar';
diff --git a/src/legacy/core_plugins/kibana/public/discover/np_ready/components/discover_grid/discover_grid.tsx b/src/legacy/core_plugins/kibana/public/discover/np_ready/components/discover_grid/discover_grid.tsx
index f1210cc2382f43..cb2b9c0e441bec 100644
--- a/src/legacy/core_plugins/kibana/public/discover/np_ready/components/discover_grid/discover_grid.tsx
+++ b/src/legacy/core_plugins/kibana/public/discover/np_ready/components/discover_grid/discover_grid.tsx
@@ -137,7 +137,7 @@ export const DiscoverGrid = React.memo(function DiscoverGridInner({
   onAddColumn,
 }: Props) {
   const actionColumnId = 'uniqueString'; // TODO should be guaranteed unique...
-  const lowestPageSize = 50;
+  const lowestPageSize = 500;
   const timeString = i18n.translate('kbn.discover.timeLabel', {
     defaultMessage: 'Time',
   });
@@ -338,7 +338,7 @@ export const DiscoverGrid = React.memo(function DiscoverGridInner({
           ...pagination,
           onChangeItemsPerPage,
           onChangePage,
-          pageSizeOptions: [lowestPageSize, 100, 500],
+          pageSizeOptions: [lowestPageSize],
         }}
         toolbarVisibility={{
           showColumnSelector: false,
diff --git a/src/legacy/core_plugins/kibana/public/discover/np_ready/components/field_chooser/field_chooser.html b/src/legacy/core_plugins/kibana/public/discover/np_ready/components/field_chooser/field_chooser.html
index 1c7435ad794a39..e406f17d682e9d 100644
--- a/src/legacy/core_plugins/kibana/public/discover/np_ready/components/field_chooser/field_chooser.html
+++ b/src/legacy/core_plugins/kibana/public/discover/np_ready/components/field_chooser/field_chooser.html
@@ -1,6 +1,8 @@
-<section class="dscFieldChooser__section" aria-label="{{::'kbn.discover.fieldChooser.filter.indexAndFieldsSectionAriaLabel' | i18n: {defaultMessage: 'Index and fields'} }}">
+<section
+  class="dscFieldChooser__section"
+  aria-label="{{::'kbn.discover.fieldChooser.filter.indexAndFieldsSectionAriaLabel' | i18n: {defaultMessage: 'Index and fields'} }}"
+>
   <div class="dscFieldChooser__sectionStatic">
-
     <discover-index-pattern-select
       selected-index-pattern="selectedIndexPattern"
       set-index-pattern="setIndexPattern"
@@ -8,11 +10,7 @@
     >
     </discover-index-pattern-select>
     <form>
-      <discover-field-search
-        on-change="setFilterValue"
-        value="filter.vals.name"
-        types="fieldTypes"
-      >
+      <discover-field-search on-change="setFilterValue" value="filter.vals.name" types="fieldTypes">
       </discover-field-search>
     </form>
   </div>
@@ -25,6 +23,7 @@
         tabindex="0"
         i18n-id="kbn.discover.fieldChooser.filter.selectedFieldsTitle"
         i18n-default-message="Selected fields"
+        data-test-subj="discover-sidebar-list-header"
       ></h3>
       <ul class="dscFieldList dscFieldList--selected" aria-labelledby="selected_fields">
         <discover-field
@@ -43,10 +42,11 @@
         tabindex="0"
         i18n-id="kbn.discover.fieldChooser.filter.availableFieldsTitle"
         i18n-default-message="Available fields"
+        data-test-subj="discover-sidebar-list-header"
+        ng-if="fields.length"
       ></h3>
     </div>
     <div class="euiFlexGroup euiFlexGroup--gutterMedium" ng-if="fields.length">
-
       <div class="euiFlexItem euiFlexItem--flexGrowZero">
         <button
           ng-click="$parent.showFields = !$parent.showFields"
@@ -65,7 +65,8 @@
     <ul
       ng-show="(popularFields | filter:filter.isFieldFilteredAndNotDisplayed).length > 0"
       ng-class="{ 'hidden-sm': !showFields, 'hidden-xs': !showFields }"
-      class="dscFieldList dscFieldList--popular">
+      class="dscFieldList dscFieldList--popular"
+    >
       <li>
         <h6
           i18n-id="kbn.discover.fieldChooser.filter.popularTitle"
@@ -85,7 +86,8 @@
 
     <ul
       ng-class="{ 'hidden-sm': !showFields, 'hidden-xs': !showFields  }"
-      class="dscFieldList dscFieldList--unpopular">
+      class="dscFieldList dscFieldList--unpopular"
+    >
       <discover-field
         ng-repeat="field in unpopularFields | filter:filter.isFieldFilteredAndNotDisplayed"
         field="field"
@@ -97,5 +99,4 @@
       </discover-field>
     </ul>
   </div>
-
 </section>
diff --git a/test/functional/page_objects/discover_page.js b/test/functional/page_objects/discover_page.js
index 5ccc5625849d27..9724395e57d47e 100644
--- a/test/functional/page_objects/discover_page.js
+++ b/test/functional/page_objects/discover_page.js
@@ -247,12 +247,12 @@ export function DiscoverPageProvider({ getService, getPageObjects }) {
     }
 
     async getAllFieldNames() {
-      const items = await find.allByCssSelector('.sidebar-item');
+      const items = await find.allByCssSelector('.dscSidebarItem');
       return await Promise.all(items.map(item => item.getVisibleText()));
     }
 
     async getSidebarWidth() {
-      const sidebar = await find.byCssSelector('.sidebar-list');
+      const sidebar = await find.byCssSelector('.dscFieldChooser__section');
       return await sidebar.getAttribute('clientWidth');
     }
 
diff --git a/x-pack/legacy/plugins/reporting/export_types/common/layouts/preserve_layout.css b/x-pack/legacy/plugins/reporting/export_types/common/layouts/preserve_layout.css
index 2c203e507260fa..fce2f7fd6a0558 100644
--- a/x-pack/legacy/plugins/reporting/export_types/common/layouts/preserve_layout.css
+++ b/x-pack/legacy/plugins/reporting/export_types/common/layouts/preserve_layout.css
@@ -34,7 +34,6 @@ filter-bar,
 
 /* hide unusable controls */
 discover-app .dscTimechart,
-discover-app .sidebar-container,
 discover-app .kbnCollapsibleSidebar__collapseButton,
 discover-app navbar[name=discover-search],
 discover-app .discover-table-footer {
diff --git a/x-pack/legacy/plugins/reporting/export_types/common/layouts/print.css b/x-pack/legacy/plugins/reporting/export_types/common/layouts/print.css
index b5c9861208b7bd..813c6eeae0b503 100644
--- a/x-pack/legacy/plugins/reporting/export_types/common/layouts/print.css
+++ b/x-pack/legacy/plugins/reporting/export_types/common/layouts/print.css
@@ -33,7 +33,6 @@ filter-bar,
 
 /* hide unusable controls */
 discover-app .dscTimechart,
-discover-app .sidebar-container,
 discover-app .kbnCollapsibleSidebar__collapseButton,
 discover-app navbar[name="discover-search"],
 discover-app .discover-table-footer {