MDL-65596 core_message: dropdown menu blocked by contact request message

message/templates/message_drawer_view_conversation_body.mustache

@@ -44,7 +44,7 @@
 >
     <div class="position-relative h-100" data-region="content-container" style="overflow-y: auto; overflow-x: hidden">
         <div class="content-message-container hidden h-100 px-2 pt-0" data-region="content-message-container" role="log" style="overflow-y: auto; overflow-x: hidden">
-            <div class="py-3 bg-light sticky-top border-bottom text-center hidden" data-region="contact-request-sent-message-container">
+            <div class="py-3 bg-light sticky-top z-index-1 border-bottom text-center hidden" data-region="contact-request-sent-message-container">
                 <p class="m-0">{{#str}} contactrequestsent, core_message {{/str}}</p>
                 <p class="font-italic font-weight-light" data-region="text"></p>
             </div>

theme/boost/scss/moodle/core.scss

@@ -2258,3 +2258,7 @@ $switch-transition: .2s all !default;
 .position-right {
     right: 0 !important; /* stylelint-disable-line declaration-no-important */
 }
+
+.z-index-1 {
+    z-index: 1 !important; /* stylelint-disable-line declaration-no-important */
+}

theme/boost/style/moodle.css

@@ -10541,6 +10541,10 @@ div.editor_atto_toolbar button .icon {
   right: 0 !important;
   /* stylelint-disable-line declaration-no-important */ }
 
+.z-index-1 {
+  z-index: 1 !important;
+  /* stylelint-disable-line declaration-no-important */ }
+
 .icon {
   font-size: 16px;
   width: 16px;

theme/bootstrapbase/less/moodle/bs4-compat.less

@@ -654,3 +654,9 @@
 .font-weight-bold {
     font-weight: 700 !important;
 }
+
+.sticky-top {
+    position: sticky;
+    top: 0;
+    z-index: 1;
+}

theme/bootstrapbase/style/moodle.css

@@ -22427,3 +22427,8 @@ ul.indented-list {
 .font-weight-bold {
   font-weight: 700 !important;
 }
+.sticky-top {
+  position: sticky;
+  top: 0;
+  z-index: 1;
+}