fix: prevents document sidebar from collapsing

packages/payload/src/admin/components/elements/DocumentFields/index.scss

@@ -7,6 +7,10 @@
 
   &--has-sidebar {
     .document-fields {
+      &__main {
+        width: 66.66%;
+      }
+
       &__edit {
         [dir='ltr'] & {
           top: 0;
@@ -52,6 +56,7 @@
     width: 33.33%;
     height: calc(100vh - var(--doc-controls-height));
     min-width: var(--doc-sidebar-width);
+    flex-shrink: 0;
   }
 
   &__sidebar {

test/fields/collections/Tabs/index.ts

@@ -12,6 +12,16 @@ const TabsFields: CollectionConfig = {
   },
   versions: true,
   fields: [
+    {
+      name: 'sidebarField',
+      type: 'text',
+      label: 'Sidebar Field',
+      admin: {
+        position: 'sidebar',
+        description:
+          'This should not collapse despite there being many tabs pushing the main fields open.',
+      },
+    },
     {
       type: 'tabs',
       tabs: [