Weston Ruter

This is a feature plugin intended to implement <a href="https://core.trac.wordpress.org/ticket/28536" rel="nofollow ugc">#28536</a>: Add browser history and deep linking for navigation in Customizer preview
This plugin keeps the Customizer URL in the browser updated with current previewed URL as the <code>url</code> query param and current expanded panel/section/control as <code>autofocus</code> params. This allows for bookmarking and also the ability to reload and return go the same view (which is great for developers), including which device you are previewing (desktop, tablet, or mobile). Not only will the URL be kept in sync with the current customizer UI, but new browser history entries will be added as you navigate around the site in the preview (via <code>history.pushState()</code>), allowing you to use the back/forward buttons as you would normally when browsing the site outside the customizer. The scroll position for each previewed URL is tracked as well, so that when you navigate back/forward the scroll position will be restored, just as happens when browsing the site outside the customizer preview. Restoring the scroll position also works when reloading the customizer, as the position is persisted in a <code>scroll</code> query parameter: again, this is extremely useful during development.
This plugin complements well the <a href="https://github.com/xwp/wp-customize-snapshots" rel="nofollow ugc">Customize Snapshots</a> plugin which allows you to save your Customizer state in a shapshot/changeset with an associated UUID that also gets added to the browser URL in the Customizer.
For example, if you load the Customizer and then click the “Site Identity” section, the URL will be replaced to add <code>autofocus[section]=title_tagline</code>.
If you navigate into the nav menus panel, open a menu section, and then expand a nav menu item control, then the URL will have these <code>autofocus</code> params added:
<pre>
autofocus[panel]=nav_menus&autofocus[section]=nav_menu[87]&autofocus[control]=nav_menu_item[5123]
</pre>
And while these changes to the <code>autofocus</code> params are being made in the browser’s URL as the Customizer UI is interacted with, if you navigate to another page in the preview the <code>url</code> parameter will also be replaced to reflect the new preview URL.
Note that the <code>url</code> param will be URL-encoded. So a typical Customizer URL would get updated to look like:
<pre>
http://example.com/wp-admin/customize.php?url=http%3A%2F%2Fexample.com%2Fsample-page%2F&autofocus[panel]=widgets&autofocus[section]=sidebar-widgets-sidebar-1&autofocus[control]=widget_text[10]&device=mobile&scroll=200
</pre>
The plugin will also persist the scroll position from the frontend to preview frame in the Customizer after clicking the “Customize” link in the frontend admin bar. This ensures you can quickly start editing whatever you were looking at the moment you clicked Customize, and it makes the Customizer load from the frontend in a more seamless way.
Additionally, as you navigate around the Customizer preview, the close link in the Customizer controls pane will keep updating to point to the same URL that you are previewing, along with persisting the scroll position. In this way, whenever you close the Customizer via this link the user experience is that the Customizer sidebar is just removed, similar to as if they clicked the “Hide Controls” link at the bottom of the sidebar. This behavior is only active if the user had clicked the Customize link from the frontend. If they clicked Customize from the admin, then the Close link will remain linking back to the admin page they came from. Note that for responsive themes like Twenty Seventeen, the synced scroll position between the frontend and backend won’t always appear seamless since the Customizer controls panel being expanded causes the element dimensions in the preview to change.
Development of this plugin is done <a href="https://github.com/xwp/wp-customizer-browser-history" rel="nofollow ugc">on GitHub</a>. Pull requests welcome. Please see <a href="https://github.com/xwp/wp-customizer-browser-history/issues" rel="nofollow ugc">issues</a> reported there before going to the <a href="https://wordpress.org/support/plugin/customizer-browser-history" rel="ugc">plugin forum</a>.

Customizer Browser History

This is a true time saver after Customizer reloads that really adds up....I've only used it for a day but I'm already so used to it I'm not sure I can do without it. Great job!



Resumable Customizer sessions are a big time saver

I was about to create a similar plugin myself, but I'm lucky to find this plugin. Now I'm happy to say that it saved me some time.

When refreshing the customizer browser frequently this plugin is really handy.

Thank you.

I was about to create a similar plugin myself, but...

Sync browser URL in Customizer with current preview URL and focused panels, sections, and controls.

Dojo Digital

This plugin adds a textarea to the Customize page that allows theme editors to write, preview, and implement CSS code in real time. 
It also includes a frontend CSS editor window with live preview capability.

Live CSS Preview

Live front-end and Customizer CSS editing powered by native WordPress Additional CSS storage.

Customizer Browser History vs Live CSS Preview