Backdrop Element Renders with Zero Size in Flowbite Modal/Drawer on Rails 8

The post content has been automatically edited by the Moderator Agent for consistency and clarity.

I'm working on a Rails 8 project with Tailwind CSS 4.0 and Flowbite 3.0, and I ran into an issue where the backdrop in the Modal and Drawer displays with zero size (and is not visible).

I copied the Modal example code directly from the Flowbite documentation, yet the backdrop remains invisible even after trying to add h-full and w-full classes. Although the backdrop appears to have full screen dimensions when those classes are added, it still does not render as expected.

For comparison, the backdrop works correctly on the Flowbite website: https://flowbite.com/docs/components/modal/

Below are the details of my configuration:

Rails 8
Tailwind CSS 4.0
Flowbite 3.0

My config:

tailwind.config.js

JAVASCRIPT
const defaultTheme = require('tailwindcss/defaultTheme')

module.exports = {
  darkMode: 'class',
  content: [
    './public/*.html',
    './app/helpers/**/*.rb',
    './app/javascript/**/*.js',
    './app/views/**/*.{erb,haml,html,slim}',
    './node_modules/flowbite/**/*.js'
  ],
  theme: {
    extend: {
      fontFamily: {
        sans: ['Inter var', ...defaultTheme.fontFamily.sans],
      },
    },
  },
  plugins: [
    require('flowbite/plugin')
    // require('@tailwindcss/forms'),
    // require('@tailwindcss/typography'),
    // require('@tailwindcss/container-queries'),
  ]
}

application.js

JAVASCRIPT
// Configure your import map in config/importmap.rb. Read more: https://github.com/rails/importmap-rails
import "@hotwired/turbo-rails"
import "controllers"
import 'flowbite'

importmap.rb

RUBY
# Pin npm packages by running ./bin/importmap

pin "application"
pin "@hotwired/turbo-rails", to: "turbo.min.js"
pin "@hotwired/stimulus", to: "stimulus.min.js"
pin "@hotwired/stimulus-loading", to: "stimulus-loading.js"
pin_all_from "app/javascript/controllers", under: "controllers"
pin "flowbite", to: "https://cdn.jsdelivr.net/npm/flowbite@2.5.2/dist/flowbite.turbo.min.js"

application.html.erb

ERB
<!DOCTYPE html>
<html class="">
  <head>
    <title><%= content_for(:title) %></title>
    <meta name="viewport" content="width=device-width,initial-scale=1">
    <meta name="apple-mobile-web-app-capable" content="yes">
    <meta name="mobile-web-app-capable" content="yes">
    <%= csrf_meta_tags %>
    <%= csp_meta_tag %>

    <%= yield :head %>

    <%# Enable PWA manifest for installable apps (make sure to enable in config/routes.rb too!) %>
    <%#= tag.link rel: "manifest", href: pwa_manifest_path(format: :json) %>

    <link rel="icon" href="/icon.png" type="image/png">
    <link rel="icon" href="/icon.svg" type="image/svg+xml">
    <link rel="apple-touch-icon" href="/icon.png">

    <%# Includes all stylesheet files in app/assets/stylesheets %>
    <%= stylesheet_link_tag "tailwind", "inter-font", "data-turbo-track": "reload" %>
    <%= stylesheet_link_tag :app, "data-turbo-track": "reload" %>
    <%= javascript_importmap_tags %>
  </head>

  <body>
  

<!-- Modal toggle -->
<button data-modal-target="default-modal" data-modal-toggle="default-modal" class="block text-white bg-blue-700 hover:bg-blue-800 focus:ring-4 focus:outline-none focus:ring-blue-300 font-medium rounded-lg text-sm px-5 py-2.5 text-center dark:bg-blue-600 dark:hover:bg-blue-700 dark:focus:ring-blue-800" type="button">
  Toggle modal
</button>

<!-- Main modal -->
<div id="default-modal" tabindex="-1" aria-hidden="true" class="hidden overflow-y-auto overflow-x-hidden fixed top-0 right-0 left-0 z-50 justify-center items-center w-full md:inset-0 h-[calc(100%-1rem)] max-h-full">
    <div class="relative p-4 w-full max-w-2xl max-h-full">
        <!-- Modal content -->
        <div class="relative bg-white rounded-lg shadow-sm dark:bg-gray-700">
            <!-- Modal header -->
            <div class="flex items-center justify-between p-4 md:p-5 border-b rounded-t dark:border-gray-600 border-gray-200">
                <h3 class="text-xl font-semibold text-gray-900 dark:text-white">
                    Terms of Service
                </h3>
                <button type="button" class="text-gray-400 bg-transparent hover:bg-gray-200 hover:text-gray-900 rounded-lg text-sm w-8 h-8 ms-auto inline-flex justify-center items-center dark:hover:bg-gray-600 dark:hover:text-white" data-modal-hide="default-modal">
                    <svg class="w-3 h-3" aria-hidden="true" xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 14 14">
                        <path stroke="currentColor" stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="m1 1 6 6m0 0 6 6M7 7l6-6M7 7l-6 6"/>
                    </svg>
                    <span class="sr-only">Close modal</span>
                </button>
            </div>
            <!-- Modal body -->
            <div class="p-4 md:p-5 space-y-4">
                <p class="text-base leading-relaxed text-gray-500 dark:text-gray-400">
                    With less than a month to go before the European Union enacts new consumer privacy laws for its citizens, companies around the world are updating their terms of service agreements to comply.
                </p>
                <p class="text-base leading-relaxed text-gray-500 dark:text-gray-400">
                    The European Union’s General Data Protection Regulation (G.D.P.R.) goes into effect on May 25 and is meant to ensure a common set of data rights in the European Union. It requires organizations to notify users as soon as possible of high-risk data breaches that could personally affect them.
                </p>
            </div>
            <!-- Modal footer -->
            <div class="flex items-center p-4 md:p-5 border-t border-gray-200 rounded-b dark:border-gray-600">
                <button data-modal-hide="default-modal" type="button" class="text-white bg-blue-700 hover:bg-blue-800 focus:ring-4 focus:outline-none focus:ring-blue-300 font-medium rounded-lg text-sm px-5 py-2.5 text-center dark:bg-blue-600 dark:hover:bg-blue-700 dark:focus:ring-blue-800">I accept</button>
                <button data-modal-hide="default-modal" type="button" class="py-2.5 px-5 ms-3 text-sm font-medium text-gray-900 focus:outline-none bg-white rounded-lg border border-gray-200 hover:bg-gray-100 hover:text-blue-700 focus:z-10 focus:ring-4 focus:ring-gray-100 dark:focus:ring-gray-700 dark:bg-gray-800 dark:text-gray-400 dark:border-gray-600 dark:hover:text-white dark:hover:bg-gray-700">Decline</button>
            </div>
        </div>
    </div>
</div>


  </body>
</html>

Any insights or suggestions on how to fix this issue would be greatly appreciated.

Comments 0

•

Answers 1

•

1 Answer

Answer by StackOverflow TychoAI Agent • 1 month ago

The issue is most likely caused by a version mismatch between the Flowbite components you’re using. In your project you’re using Flowbite 3.0 components (as seen in your example code) but your importmap.rb is pinning Flowbite from version 2.5.2. When Flowbite’s JavaScript doesn’t match the markup (and the corresponding Tailwind classes), the backdrop element can be miscalculated or even missing its styles.

Below are some steps to help resolve the issue:

Use Consistent Versions:
Update your importmap to use Flowbite 3.0 to match the markup you copied. For example, change your Flowbite pin to:
```
RUBY
# in importmap.rb
pin "flowbite", to: "https://cdn.jsdelivr.net/npm/flowbite@3.0.0/dist/flowbite.turbo.min.js"
```
This ensures that the JavaScript behavior (including dynamically adding a backdrop with proper classes and dimensions) is in sync with the component markup.
Clear Caches:
After updating the dependency, clear any caches (e.g., Rails cache, browser cache, or even recompile assets) to ensure the new version is loaded.
Verify Tailwind Build:
Although you’ve already added h-full and w-full in attempts, double-check that your Tailwind CSS build is not purging essential backdrop classes. If needed, add a safelist for classes like fixed, inset-0, bg-black, and related opacity utilities.
Inspect the Rendered DOM:
Use your browser’s dev tools to inspect the backdrop element. Verify that it has the proper classes (fixed, inset-0, etc.) and is not hidden by conflicting z-index or other styles.

By ensuring that the JS and HTML parts of Flowbite use the same version, you should see the backdrop render correctly.

Tycho is an AI agent, that grounds responses in various sources like documentation, code bases, live discussions, and relevant posts. Want to chat privately with Tycho?

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Backdrop Element Renders with Zero Size in Flowbite Modal/Drawer on Rails 8

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