diff --git a/theme/boost/scss/moodle/bs4alphacompat.scss b/theme/boost/scss/moodle/bs4alphacompat.scss
index a017c2c948d..4d01c212437 100644
--- a/theme/boost/scss/moodle/bs4alphacompat.scss
+++ b/theme/boost/scss/moodle/bs4alphacompat.scss
@@ -173,6 +173,10 @@ $tag-font-weight: bold !default;
     @include float-right();
 }
 
+.custom-select {
+    width: auto;
+}
+
 .fade.in {
     opacity: 1;
 }
diff --git a/theme/boost/style/moodle.css b/theme/boost/style/moodle.css
index a0e4db7f006..94feba3fdee 100644
--- a/theme/boost/style/moodle.css
+++ b/theme/boost/style/moodle.css
@@ -8594,6 +8594,9 @@ a.dimmed_text:visited,
   #page-admin-report-backups-index .backup-unfinished[href]:focus, #page-admin-index .adminwarning.availableupdatesinfo .moodleupdateinfo.maturity50 .info.release[href]:focus {
     background-color: #c9302c; }
 
+.custom-select {
+  width: auto; }
+
 .fade.in {
   opacity: 1; }
 
diff --git a/theme/boost/templates/core/filemanager_fileselect.mustache b/theme/boost/templates/core/filemanager_fileselect.mustache
index ca9d291f4cc..64fb76e5aa0 100644
--- a/theme/boost/templates/core/filemanager_fileselect.mustache
+++ b/theme/boost/templates/core/filemanager_fileselect.mustache
@@ -2,8 +2,8 @@
     <div class="fp-select-loading">
         {{#pix}}i/loading_small{{/pix}}
     </div>
-    <form class="form clearfix">
-        <div class="form-group">
+    <form class="mform clearfix">
+        <div class="form-group mx-0">
             <button class="fp-file-download btn btn-secondary">{{#str}}download{{/str}}</button>
             <button class="fp-file-delete btn btn-secondary">{{#str}}delete{{/str}}</button>
             <button class="fp-file-setmain btn btn-secondary">{{#str}}setmainfile, repository{{/str}}</button>
@@ -12,36 +12,36 @@
             <button class="fp-file-unzip btn btn-secondary">{{#str}}unzip{{/str}}</button>
         </div>
 
-                <div class="fp-saveas form-group row">
-                    <label class="form-control-label col-4">{{#str}}name, repository{{/str}}</label>
-                    <div class="col-8"><input class="form-control" type="text"/></div>
+                <div class="fp-saveas form-group row mx-0">
+                    <label class="form-control-label col-4 px-0">{{#str}}name, repository{{/str}}</label>
+                    <div class="col-8 form-inline"><input class="form-control" type="text"/></div>
                 </div>
-                <div class="fp-author form-group row">
-                    <label class="form-control-label col-4">{{#str}}author, repository{{/str}}</label>
-                    <div class="col-8"><input class="form-control" type="text"/></div>
+                <div class="fp-author form-group row mx-0">
+                    <label class="form-control-label col-4 px-0">{{#str}}author, repository{{/str}}</label>
+                    <div class="col-8 form-inline"><input class="form-control" type="text"/></div>
 
                 </div>
-                <div class="fp-license form-group row">
-                    <label class="form-control-label col-4">{{#str}}chooselicense, repository{{/str}}</label>
-                    <div class="col-8">
-                        <select class="custom-select"></select>
+                <div class="fp-license form-group row mx-0">
+                    <label class="form-control-label col-4 px-0">{{#str}}chooselicense, repository{{/str}}</label>
+                    <div class="col-8 form-inline pr-0">
+                        <select class="custom-select form-control"></select>
                     </div>
                 </div>
-                <div class="fp-path form-group row">
-                    <label class="form-control-label col-4">{{#str}}path, repository{{/str}}</label>
-                    <div class="col-8">
-                        <select class="custom-select"></select>
+                <div class="fp-path form-group row mx-0">
+                    <label class="form-control-label col-4 px-0">{{#str}}path, repository{{/str}}</label>
+                    <div class="col-8 form-inline pr-0">
+                        <select class="custom-select form-control"></select>
                     </div>
                 </div>
-                <div class="fp-original form-group row">
-                    <label class="form-control-label col-4">{{#str}}original, repository{{/str}}</label>
-                    <div class="col-8">
+                <div class="fp-original form-group row mx-0">
+                    <label class="form-control-label col-4 px-0">{{#str}}original, repository{{/str}}</label>
+                    <div class="col-8 form-inline">
                         <span class="fp-originloading">{{#pix}}i/loading_small{{/pix}} {{#str}}loading, repository{{/str}}</span><span class="fp-value"></span>
                     </div>
                 </div>
-                <div class="fp-reflist form-group row">
-                    <label class="form-control-label col-4">{{#str}}referenceslist, repository{{/str}}</label>
-                    <div class="col-8">
+                <div class="fp-reflist form-group row mx-0">
+                    <label class="form-control-label col-4 px-0">{{#str}}referenceslist, repository{{/str}}</label>
+                    <div class="col-8 form-inline">
                         <p class="fp-refcount"></p>
                         <span class="fp-reflistloading">{{#pix}}i/loading_small{{/pix}} {{#str}}loading, repository{{/str}}</span>
                         <ul class="fp-value"></ul>