diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
index 146b9fd68e..1f6ef85990 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
@@ -304,8 +304,10 @@ public static function generateSampleValue(FieldDefinitionInterface $field_defin
     // entities created.
     if ($referenceable = $selection_handler->getReferenceableEntities(NULL, 'CONTAINS', 50)) {
       $group = array_rand($referenceable);
-      $values['target_id'] = array_rand($referenceable[$group]);
-      return $values;
+      if (!empty($referenceable[$group])) {
+        $values['target_id'] = array_rand($referenceable[$group]);
+        return $values;
+      }
     }
 
     // Attempt to create a sample entity, avoiding recursion.
diff --git a/core/modules/layout_builder/tests/src/FunctionalJavascript/InlineBlockTestBase.php b/core/modules/layout_builder/tests/src/FunctionalJavascript/InlineBlockTestBase.php
index dbf68d6179..e40536ab2e 100644
--- a/core/modules/layout_builder/tests/src/FunctionalJavascript/InlineBlockTestBase.php
+++ b/core/modules/layout_builder/tests/src/FunctionalJavascript/InlineBlockTestBase.php
@@ -110,18 +110,23 @@ protected function getLatestBlockEntityId() {
   /**
    * Removes an entity block from the layout but does not save the layout.
    */
-  protected function removeInlineBlockFromLayout() {
+  protected function removeInlineBlockFromLayout($selector = NULL) {
+    $selector = $selector ?? static::INLINE_BLOCK_LOCATOR;
     $assert_session = $this->assertSession();
     $page = $this->getSession()->getPage();
-    $block_text = $page->find('css', static::INLINE_BLOCK_LOCATOR)->getText();
+    $block_text = $page->find('css', $selector)->getText();
     $this->assertNotEmpty($block_text);
     $assert_session->pageTextContains($block_text);
-    $this->clickContextualLink(static::INLINE_BLOCK_LOCATOR, 'Remove block');
+    $this->clickContextualLink($selector, 'Remove block');
     $assert_session->waitForElement('css', "#drupal-off-canvas input[value='Remove']");
     $assert_session->assertWaitOnAjaxRequest();
+
+    // Output the new HTML.
+    $this->htmlOutput($page->getHtml());
+
     $page->find('css', '#drupal-off-canvas')->pressButton('Remove');
     $assert_session->assertNoElementAfterWait('css', '#drupal-off-canvas');
-    $assert_session->assertNoElementAfterWait('css', static::INLINE_BLOCK_LOCATOR);
+    $assert_session->assertNoElementAfterWait('css', $selector);
     $assert_session->assertWaitOnAjaxRequest();
     $assert_session->pageTextNotContains($block_text);
   }
diff --git a/core/modules/layout_builder/tests/src/FunctionalJavascript/WorkspacesBlockTest.php b/core/modules/layout_builder/tests/src/FunctionalJavascript/WorkspacesBlockTest.php
new file mode 100644
index 0000000000..070c4ea7a0
--- /dev/null
+++ b/core/modules/layout_builder/tests/src/FunctionalJavascript/WorkspacesBlockTest.php
@@ -0,0 +1,173 @@
+<?php
+
+namespace Drupal\Tests\layout_builder\FunctionalJavascript;
+
+use Drupal\Tests\system\Traits\OffCanvasTestTrait;
+use Drupal\Tests\workspaces\Functional\WorkspaceTestUtilities;
+use Drupal\workspaces\Entity\Workspace;
+
+/**
+ * Tests for layout editing in workspaces.
+ *
+ * @group layout_builder
+ */
+class WorkspacesBlockTest extends InlineBlockTestBase {
+
+  use OffCanvasTestTrait;
+  use WorkspaceTestUtilities;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'starterkit_theme';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'field_ui',
+    'workspaces',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+    $this->drupalLogin($this->drupalCreateUser([
+      'access contextual links',
+      'configure any layout',
+      'administer node display',
+      'administer node fields',
+      'create and edit custom blocks',
+      'administer blocks',
+      'administer content types',
+      'administer workspaces',
+      'view any workspace',
+      'administer site configuration',
+      'administer nodes',
+      'bypass node access',
+    ]));
+    $this->setupWorkspaceSwitcherBlock();
+
+    // Enable layout builder.
+    $this->drupalGet(static::FIELD_UI_PREFIX . '/display/default');
+    $this->submitForm([
+      'layout[enabled]' => TRUE,
+      'layout[allow_custom]' => TRUE,
+    ], 'Save');
+    $this->clickLink('Manage layout');
+    $this->assertSession()->addressEquals(static::FIELD_UI_PREFIX . '/display/default/layout');
+    // Add a basic block with the body field set.
+    $this->addInlineBlockToLayout('Block title', 'The DEFAULT block body');
+    $this->assertSaveLayout();
+  }
+
+  /**
+   * Tests changing a layout/blocks inside a workspace.
+   */
+  public function testBlocksInWorkspaces() {
+    $assert_session = $this->assertSession();
+    $this->drupalGet('node/1');
+    $assert_session->pageTextContains('The DEFAULT block body');
+    $this->drupalGet('node/2');
+    $assert_session->pageTextContains('The DEFAULT block body');
+
+    $stage = Workspace::load('stage');
+    $this->switchToWorkspace($stage);
+
+    // Confirm the block can be edited.
+    $this->drupalGet('node/1/layout');
+    $new_block_body = 'The NEW block body';
+    $this->configureInlineBlock('The DEFAULT block body', $new_block_body);
+    $this->assertSaveLayout();
+
+    $this->drupalGet('node/1');
+    $assert_session->pageTextContains($new_block_body);
+    $assert_session->pageTextNotContains('The DEFAULT block body');
+    $this->drupalGet('node/2');
+    // Node 2 should use default layout.
+    $assert_session->pageTextContains('The DEFAULT block body');
+    $assert_session->pageTextNotContains($new_block_body);
+
+    // Switch back to the live workspace and verify that the changes are not
+    // visible there.
+    $this->switchToLive();
+    $this->drupalGet('node/1');
+    $assert_session->pageTextNotContains($new_block_body);
+    $assert_session->pageTextContains('The DEFAULT block body');
+
+    $this->switchToWorkspace($stage);
+    // Add a basic block with the body field set.
+    $this->drupalGet('node/1/layout');
+    $second_block_body = 'The 2nd block body';
+    $this->addInlineBlockToLayout('2nd Block title', $second_block_body);
+    $this->assertSaveLayout();
+    $this->drupalGet('node/1');
+    $assert_session->pageTextContains($second_block_body);
+    $this->drupalGet('node/2');
+    // Node 2 should use default layout.
+    $assert_session->pageTextContains('The DEFAULT block body');
+    $assert_session->pageTextNotContains($new_block_body);
+    $assert_session->pageTextNotContains($second_block_body);
+
+    // Switch back to the live workspace and verify that the new added block is
+    // not visible there.
+    $this->switchToLive();
+    $this->drupalGet('node/1');
+    $assert_session->pageTextNotContains($second_block_body);
+    $assert_session->pageTextContains('The DEFAULT block body');
+
+    $stage->publish();
+    $this->drupalGet('node/1');
+    $assert_session->pageTextNotContains('The DEFAULT block body');
+    $assert_session->pageTextContains($new_block_body);
+    $assert_session->pageTextContains($second_block_body);
+  }
+
+  /**
+   * Tests that blocks can be deleted inside workspaces.
+   */
+  public function testBlockDeletionInWorkspaces() {
+    $assert_session = $this->assertSession();
+
+    $stage = Workspace::load('stage');
+    $this->switchToWorkspace($stage);
+
+    $this->drupalGet('node/1/layout');
+    $workspace_block_content = 'The WORKSPACE block body';
+    $this->addInlineBlockToLayout('Workspace block title', $workspace_block_content);
+    $this->assertSaveLayout();
+
+    $this->drupalGet('node/1');
+    $assert_session->pageTextContains('The DEFAULT block body');
+    $assert_session->pageTextContains($workspace_block_content);
+
+    $this->switchToLive();
+    $assert_session->pageTextNotContains($workspace_block_content);
+
+    $this->switchToWorkspace($stage);
+    $this->drupalGet('node/1/layout');
+    $this->removeInlineBlockFromLayout(static::INLINE_BLOCK_LOCATOR . ' ~ ' . static::INLINE_BLOCK_LOCATOR);
+    $this->assertSaveLayout();
+    $this->drupalGet('node/1');
+    $assert_session->pageTextContains('The DEFAULT block body');
+    $assert_session->pageTextNotContains($workspace_block_content);
+
+    $this->drupalGet('node/1/layout');
+    $this->removeInlineBlockFromLayout();
+    $this->assertSaveLayout();
+    $this->drupalGet('node/1');
+    $assert_session->pageTextNotContains('The DEFAULT block body');
+    $assert_session->pageTextNotContains($workspace_block_content);
+
+    $this->switchToLive();
+    $this->drupalGet('node/1');
+    $assert_session->pageTextContains('The DEFAULT block body');
+    $stage->publish();
+    $this->drupalGet('node/1');
+    $assert_session->pageTextNotContains('The DEFAULT block body');
+    $assert_session->pageTextNotContains($workspace_block_content);
+  }
+
+}