I recently updated my Horizon theme from version 4.14 to 4.15, and since the update I have been experiencing several problems with my website.
The main issues are:
My website feels slower and gets stuck more frequently.
The cart I installed through an app is no longer responding properly.
The Sticky Add to Cart feature on the desktop/PC version is not responding correctly.
The desktop version of my website becomes misconfigured after certain interactions or while scrolling.
Some elements that previously worked correctly in version 4.14 are now behaving differently or incorrectly.
I would like to keep the Sticky Add to Cart and the cart app active. I don’t want to disable or remove these features. I need help identifying what changed between Horizon 4.14 and 4.15 and fixing the compatibility or JavaScript issues causing these problems.
Could you please help me investigate and resolve these issues? Thank you.
The issue is likely caused by JS event conflicts. Horizon 4.1.5 refactored cart drawer events and sticky element listeners, which breaks how older app scripts bind to the DOM.
Check your browser console (F12) while scrolling or clicking the cart—you’ll likely see script execution errors. Re-indexing the app script triggers to the new theme selectors should resolve this without removing your apps.
The timing makes the theme update worth investigating first. The 4.1.5 release notes include several cart, app-block, layout, and performance fixes, but the notes you shared don’t specifically identify a Sticky Add to Cart change.
I checked your store and noticed a few issues after updating Horizon from 4.14 to 4.15.
There are repeated Swiper loop errors, JavaScript conflicts involving the AOV Cart Drawer and Avada Free Gifts, and a stylesheet loading with an incorrect MIME type.
These issues are affecting the cart, Sticky Add to Cart, and the desktop layout during scrolling and interactions.
I’d be happy to work on these issues and get everything working properly again while keeping your existing apps and Sticky Add to Cart active.
Alternatively, you can also contact the app support teams, as some of these issues are related to the app scripts and they may be able to fix them from their side.
Regarding your custom Liquid and announcement bar:
Custom Liquid (PC): Check if your liquid container has a desktop utility class like small-hide or a @media (min-width: 750px) rule forcing display: none.
Sticky Announcement Bar: Disable it via Theme Customize > Announcement Bar, or add this CSS to your theme file:
Thanks for clarifying. Since the Add to Cart is custom Liquid, and the announcement bar also changed behavior on desktop after the theme update, I’d first check whether the custom code is still the same as it was before the Horizon update. If the code hasn’t changed, the next step would be to compare the behavior in your previous theme version and check for any desktop-only JavaScript or CSS conflicts.
For the announcement bar, can you confirm whether it was already set to sticky before the update, or did it only become sticky after updating to 4.1.5
Sure. I can help investigate these issues. I’ll check the changes between Horizon 4.14 and 4.15, especially the JavaScript, Sticky Add to Cart, and cart app compatibility, and identify what is causing the performance and layout issues.
I’ll keep both the Sticky Add to Cart and cart app active while working on the fixes.
Checked the live store directly. Couldn’t run a full console/JS trace through a page fetch, but I did notice something separate worth fixing regardless of the theme-update issue: two of your top navigation links are mislabeled. “Velvora” in the header nav actually links to your Terms of Service page, and “Contacto” links to what appears to be a duplicate Returns policy page, not an actual contact page. Worth checking Online Store > Navigation and fixing those link targets, since a visitor clicking “Contacto” expecting a contact form or email and landing on a returns policy is a real trust and usability issue independent of the JavaScript conflicts.
On the actual JS conflict diagnosis: given two people have already independently pointed at app script conflicts (AOV Cart Drawer, Avada Free Gifts) rather than the theme itself, a clean way to confirm this yourself before anyone works on it: temporarily disable each cart-related app one at a time (Settings > Apps, or the app embed toggle in Theme Customize if they inject via embed) and reload the desktop site after each one, checking whether the Sticky Add to Cart and console errors clear up. If disabling one specific app resolves it, you’ve confirmed the root cause is that app’s script not being compatible with Horizon 4.15’s updated cart drawer/sticky element event structure, which is a much faster fix (reporting it to that app’s support with the specific error) than treating it as a broader theme compatibility investigation.
Thanks for clarifying. Since the Add to Cart is custom Liquid, I’d first check whether the custom code was working on desktop before the Horizon update, because the update and the custom code could be interacting differently.
For the announcement bar, was it already sticky before the update, or did it become sticky only after updating to 4.1.5? That would help narrow down whether we’re looking at a theme setting or a code/behavior change.
I wouldn’t disable either feature yet. Since everything started immediately after the Horizon update, I’d treat the theme update as the first suspect, especially if the cart app and Sticky Add to Cart were working normally on 4.14.
I’d first compare the 4.14 and 4.15 theme code, particularly the JavaScript handling the cart, product forms, sections being re-rendered, and anything related to scroll or sticky elements. A theme update can change the way sections are loaded or replaced, and an app that was relying on the old DOM structure can suddenly stop responding even though the app itself hasn’t changed.
I’d also open the browser console on 4.15 and reproduce the problems while watching for JavaScript errors. If the cart stops responding or the desktop layout breaks after scrolling, there’s a good chance you’ll see an error around the same time. That will be much more useful than randomly disabling features.
Before changing anything on the live theme, I’d duplicate the current 4.15 theme and test the fixes there. I’d also check whether the app developer has specifically confirmed compatibility with Horizon 4.15, since this sounds more like an interaction between the theme’s updated JS and the app than a simple performance issue.
For the slower behavior, I’d run the store through SiteGuru as a separate check. That can help identify technical issues that may have appeared around the update, but I’d still use the browser console and theme code to track down the actual JavaScript conflict.
If you can share the exact console error from 4.15 and the relevant 4.14/4.15 theme files, that would make it much easier to pinpoint what actually changed rather than guessing.
Because the problems started immediately after the theme update, I would treat this as a reproducible theme/app conflict and keep the live store on the known-good theme copy while testing the new version:
Duplicate both the working and updated themes; test only in the unpublished updated copy.
Reproduce each issue with DevTools Console and Network open, and save the first error rather than the follow-on errors.
Disable cart-related app embeds one at a time in the test copy. If the cart and sticky ATC recover, re-enable them individually to identify the conflict.
Compare the cart drawer event hooks, section re-rendering, custom Liquid/JS, and desktop-only media queries between versions.
Test product → cart drawer → quantity change → checkout on desktop and mobile, then keep the working theme as a rollback until every check passes.
A same-theme update and a switch to an unrelated theme are different: compatible editor settings may transfer within the same theme family, but custom Liquid/JavaScript, app embeds, pixels, and cart events are common failure points.
Disclosure: I’m part of the Nocturne theme team. The worksheet is usable with Horizon or any other theme, and a “not compatible” result is a valid outcome—not a recommendation to change themes.
