diff --git a/mod/forum/discuss.php b/mod/forum/discuss.php
index 2bb4a415708..bccea71c822 100644
--- a/mod/forum/discuss.php
+++ b/mod/forum/discuss.php
@@ -294,7 +294,7 @@ $neighbourlinks = $renderer->neighbouring_discussion_navigation($neighbours['pre
 echo $neighbourlinks;
 
 /// Print the controls across the top
-echo '<div class="discussioncontrols clearfix"><div class="controlscontainer">';
+echo '<div class="discussioncontrols clearfix"><div class="controlscontainer m-b-1">';
 
 if (!empty($CFG->enableportfolios) && has_capability('mod/forum:exportdiscussion', $modcontext)) {
     require_once($CFG->libdir.'/portfoliolib.php');
diff --git a/theme/boost/scss/moodle/modules.scss b/theme/boost/scss/moodle/modules.scss
index 1ec5dc3f051..eb26be462bc 100644
--- a/theme/boost/scss/moodle/modules.scss
+++ b/theme/boost/scss/moodle/modules.scss
@@ -148,6 +148,10 @@ select {
 #page-mod-forum-discuss .discussioncontrols {
     width: auto;
     margin: 0;
+
+    .form-inline input {
+        margin-top: -1px;
+    }
 }
 
 .maincalendar .calendarmonth td,
diff --git a/theme/boost/templates/core/url_select.mustache b/theme/boost/templates/core/url_select.mustache
index 3b8d99b91f4..572a98aa389 100644
--- a/theme/boost/templates/core/url_select.mustache
+++ b/theme/boost/templates/core/url_select.mustache
@@ -10,7 +10,7 @@
             {{#helpicon}}
                 {{>core/help_icon}}
             {{/helpicon}}
-            <select {{#attributes}}{{name}}="{{value}}" {{/attributes}} id="{{id}}" class="form-control {{classes}}" name="jump">
+            <select {{#attributes}}{{name}}="{{value}}" {{/attributes}} id="{{id}}" class="custom-select {{classes}}" name="jump">
                 {{#options}}
                     {{#isgroup}}
                         <optgroup label="{{name}}">