Fixed create merge request dropdown re-opening

Fixes a bug where if the user types a invalid
source branch in the create merge request dropdown
it would not be able to be re-opened.

Closes https://gitlab.com/gitlab-org/gitlab/-/issues/235185

app/assets/javascripts/create_merge_request_dropdown.js

@@ -168,9 +168,6 @@ export default class CreateMergeRequestDropdown {
 
   disable() {
     this.disableCreateAction();
-
-    this.dropdownToggle.classList.add('disabled');
-    this.dropdownToggle.setAttribute('disabled', 'disabled');
   }
 
   disableCreateAction() {
@@ -189,9 +186,6 @@ export default class CreateMergeRequestDropdown {
 
     this.createTargetButton.classList.remove('disabled');
     this.createTargetButton.removeAttribute('disabled');
-
-    this.dropdownToggle.classList.remove('disabled');
-    this.dropdownToggle.removeAttribute('disabled');
   }
 
   static findByValue(objects, ref, returnFirstMatch = false) {

app/assets/stylesheets/pages/issues.scss

@@ -188,6 +188,12 @@ ul.related-merge-requests > li {
       border-width: 1px;
       line-height: $line-height-base;
       width: auto;
+
+      &.disabled {
+        background-color: $gray-light;
+        border-color: $gray-100;
+        color: $gl-text-color-disabled;
+      }
     }
   }
 

changelogs/unreleased/ph-235185-fixCreateMRDropdownReopen.yml

+---
+title: Fixed create merge request dropdown not re-opening after typing invalid source
+  branch
+merge_request: 46802
+author:
+type: fixed