diff --git a/modules/system/assets/ui/docs/select.md b/modules/system/assets/ui/docs/select.md
index 4e475d9ec..e8f18c6bd 100644
--- a/modules/system/assets/ui/docs/select.md
+++ b/modules/system/assets/ui/docs/select.md
@@ -1,6 +1,5 @@
 # Select
 
-
 ### Select
 
 Custom select control.
@@ -18,7 +17,7 @@ Custom select control.
     <div class="form-group form-group-sm">
         <select class="form-control custom-select">
             <option value="1" selected="selected">One</option>
-            <option value="2" selected="selected">Two</option>
+            <option value="2">Two</option>
         </select>
     </div>
 
@@ -27,7 +26,7 @@ Custom select control.
     <div class="form-group form-group-lg">
         <select class="form-control custom-select">
             <option value="1" selected="selected">One</option>
-            <option value="2" selected="selected">Two</option>
+            <option value="2">Two</option>
         </select>
     </div>
 
@@ -44,6 +43,20 @@ Add the `select-no-search` CSS class to disable searching.
         </select>
     </div>
 
+## Option groups
+
+Use the `optgroup` element to create option groups.
+
+    <select class="form-control custom-select">
+        <option value="1">Please select an option</option>
+        <option value="2">Ungrouped option</option>
+        <optgroup label="Option Group">
+            <option value="3">Grouped option</option>
+            <option value="4">Another option</option>
+            <option value="4">Third option</option>
+        </optgroup>
+    </select>
+
 ## AJAX search
 
 Use the `data-handler` attribute to source the select options from an AJAX handler.
diff --git a/modules/system/assets/ui/less/select.less b/modules/system/assets/ui/less/select.less
index 18aa23aff..cfbeb6fd1 100644
--- a/modules/system/assets/ui/less/select.less
+++ b/modules/system/assets/ui/less/select.less
@@ -138,10 +138,10 @@
     .select2-results__group {
         color: @color-select-header;
         display: block;
-        padding: @padding-base-vertical @padding-base-horizontal;
-        font-size: @font-size-small;
+        padding: @padding-base-vertical 6px;
         line-height: @line-height-base;
         white-space: nowrap;
+        font-weight: 500;
     }
 
     &.select2-container--focus,
diff --git a/modules/system/assets/ui/storm.css b/modules/system/assets/ui/storm.css
index 2e83bb7c5..fb2068dba 100644
--- a/modules/system/assets/ui/storm.css
+++ b/modules/system/assets/ui/storm.css
@@ -2312,7 +2312,7 @@ html.cssanimations .cursor-loading-indicator.hide{display:none}
 .select2-container--default .select2-results__option .select2-results__option .select2-results__option .select2-results__option .select2-results__option{margin-left:-39px;padding-left:52px}
 .select2-container--default .select2-results__option .select2-results__option .select2-results__option .select2-results__option .select2-results__option .select2-results__option{margin-left:-52px;padding-left:65px}
 .select2-container--default .select2-results__option .select2-results__option .select2-results__option .select2-results__option .select2-results__option .select2-results__option .select2-results__option{margin-left:-65px;padding-left:78px}
-.select2-container--default .select2-results__group{color:#999999;display:block;padding:8px 13px;font-size:12px;line-height:1.42857143;white-space:nowrap}
+.select2-container--default .select2-results__group{color:#999999;display:block;padding:8px 6px;line-height:1.42857143;white-space:nowrap;font-weight:500}
 .select2-container--default.select2-container--focus .select2-selection,.select2-container--default.select2-container--open .select2-selection{-webkit-transition:border-color ease-in-out 0.15s,box-shadow ease-in-out 0.15s;transition:border-color ease-in-out 0.15s,box-shadow ease-in-out 0.15s;border-color:#d1d6d9}
 .select2-container--default.select2-container--open .select2-selection .select2-selection__arrow b:before{font-family:FontAwesome;font-weight:normal;font-style:normal;text-decoration:inherit;-webkit-font-smoothing:antialiased;*margin-right:.3em;content:"\f106"}
 .select2-container--default.select2-container--open.select2-container--below .select2-selection:not(.select-no-dropdown){border-bottom-right-radius:0;border-bottom-left-radius:0;border-bottom-color:transparent}