diff --git a/x-pack/legacy/plugins/index_management/public/app/sections/home/index_list/detail_panel/edit_settings_json/edit_settings_json.js b/x-pack/legacy/plugins/index_management/public/app/sections/home/index_list/detail_panel/edit_settings_json/edit_settings_json.js
index a478eaceb7a20..34c958c2c346e 100644
--- a/x-pack/legacy/plugins/index_management/public/app/sections/home/index_list/detail_panel/edit_settings_json/edit_settings_json.js
+++ b/x-pack/legacy/plugins/index_management/public/app/sections/home/index_list/detail_panel/edit_settings_json/edit_settings_json.js
@@ -67,7 +67,8 @@ export class EditSettingsJson extends React.PureComponent {
       const editor = (this.editor = createAceEditor(this.aceDiv, prettyJson, false, settingsKeys));
       const session = editor.getSession();
       session.on('changeAnnotation', () => {
-        this.setState({ valid: session.getAnnotations().length === 0 });
+        const isEmptyString = session.getValue() === '';
+        this.setState({ valid: !isEmptyString && session.getAnnotations().length === 0 });
       });
     }
   }
diff --git a/x-pack/legacy/plugins/index_management/public/app/sections/home/index_list/index_actions_context_menu/index_actions_context_menu.js b/x-pack/legacy/plugins/index_management/public/app/sections/home/index_list/index_actions_context_menu/index_actions_context_menu.js
index df83e5fe2a559..9b3e30f04d901 100644
--- a/x-pack/legacy/plugins/index_management/public/app/sections/home/index_list/index_actions_context_menu/index_actions_context_menu.js
+++ b/x-pack/legacy/plugins/index_management/public/app/sections/home/index_list/index_actions_context_menu/index_actions_context_menu.js
@@ -13,7 +13,7 @@ import {
   EuiButton,
   EuiCallOut,
   EuiContextMenu,
-  EuiFieldText,
+  EuiFieldNumber,
   EuiForm,
   EuiFormRow,
   EuiPopover,
@@ -367,7 +367,7 @@ export class IndexActionsContextMenu extends Component {
           <EuiSpacer size="m" />
 
           <EuiForm
-            isInvalid={this.forcemergeSegmentsError()}
+            isInvalid={!!this.forcemergeSegmentsError()}
             error={this.forcemergeSegmentsError()}
           >
             <EuiFormRow
@@ -379,10 +379,11 @@ export class IndexActionsContextMenu extends Component {
               )}
               helpText={helpText}
             >
-              <EuiFieldText
+              <EuiFieldNumber
                 onChange={event => {
                   this.setState({ forcemergeSegments: event.target.value });
                 }}
+                min={1}
                 name="maxNumberSegments"
               />
             </EuiFormRow>