Custom block types are missing from add block - other

I tried setting Inline blocks and Custom block types to Allow all existing & new Custom block types blocks. After saving, I've got these errors both twice:

• User warning: The following theme is missing from the file system: toolbar in Drupal\Core\Extension\ExtensionPathResolver->getPathname() (line 63 of core/lib/Drupal/Core/Extension/ExtensionPathResolver.php).
• Deprecated function: dirname(): Passing null to parameter #1 ($path) of type string is deprecated in Drupal\Core\Extension\ExtensionPathResolver->getPath() (line 85 of core/lib/Drupal/Core/Extension/ExtensionPathResolver.php).

When I go to the layout edit page and add a block then, only a few show up, not the ones that I actually want.

Not sure if its helpful, this is the devel output for the 'Text' block type. Again: that shows up and works as Promoted block, but I cannot seem to get it shown on the Other tab, just like all my other custom block types.

I might have figured it out by copparing modules/contrib/lb_plus/src/Element/LayoutBuilderPlusUI.php to modules/contrib/layout_builder_browser/src/Controller/BrowserController.php on how to list blocks.
Testing this patch in a moment.

Hmm strange... If you disable LB+ do you get the results your after in regular Layout Builder? Is it a Layout Builder Restrictions problem? I thought we had it dialed in to where LB+ is acting the same as regular Layout Builder. 🤔

If I disable LB+ then I do get the results I'm after: I see the blocks that I'm missing in lb_plus. BUT this is not form a clean Layout Builder.
I enabled lb_plus for testing in a project that already had lots of layoutbuilder settings and configuration from other contrib modules:

• bootstrap_layout_builder
• bootstrap_styles
• layout_builder_blocks
• layout_builder_browser
• layout_builder_modal
• layout_builder_restrictions

So it might be from one of them. I'll see if its possible to test disabling most of those modules in my test project. If I succeed, I will report back.

I disabled layout_builder_restrictions, layout_builder_browser, layout_builder_modal.
Without lb_plus: custom inline block types are available
With lb_plus: custom inline block types are not available inside Edit layout -> Add block (+ icon in the bottom bar) -> 'Other' tab.

My custom inline blocks are available if I make specific adjustments to lb_plus/src/Element/LayoutBuilderPlusUI.php
If I change this:

    if ($layout_builder_type === 'layout_block') {
      // Include fields from the parent entity.
      $parent_definitions = $this->blockManager->getFilteredDefinitions('layout_builder', $this->getPopulatedContexts($section_storage), [
        'section_storage' => $section_storage,
      ]);
      foreach ($parent_definitions as $name => $parent_definition) {
        if (str_contains($name, 'field_block:')) {
          $definitions[$name] = $parent_definition;
        }
      }
    }

Into (adding extra new code below):

    // Add field blocks.
    if ($layout_builder_type === 'layout_block') {
      // Include fields from the parent entity.
      $parent_definitions = $this->blockManager->getFilteredDefinitions('layout_builder', $this->getPopulatedContexts($section_storage), [
        'section_storage' => $section_storage,
      ]);
      foreach ($parent_definitions as $name => $parent_definition) {
        if (str_contains($name, 'field_block:')) {
          $definitions[$name] = $parent_definition;
        }
      }
    }

    // Add custom inline blocks.
    if ($layout_builder_type === 'entity') {
      $parent_definitions = $this->blockManager->getFilteredDefinitions('layout_builder', $this->getPopulatedContexts($section_storage), [
        'section_storage' => $section_storage,
        'list' => 'inline_blocks',
      ]);
      foreach ($parent_definitions as $name => $parent_definition) {
        if (str_contains($name, 'inline_block:')) {
          $definitions[$name] = $parent_definition;
        }
      }
    }

If I do that then my custom inline block types are available.

I actually added this bit of code to the MR from #3404515 ✨ Improve Icon Selection/Upload Active because I needed both this fix as well as the icon improvements to set an icon for every block type, not just promoted blocks. And I could not get both to work using a patch for the issue here and an MR for the issue there, so I did not include this patch from this issue in my project and instead only included the MR from #3404515 ✨ Improve Icon Selection/Upload Active which now fixes both problems. Maybe not ideal so any feedback welcome if there is a better way.