Hi there! It sounds like when you add books to your cart on the BookBub app or website using your Windows device with the WebKit browser, the page or elements start jumping around, preventing you from proceeding. I want to make sure I fully understand—does the entire page move erratically, or do individual items in your cart move? Also, is this happening every time you try to check out, or only after adding a certain number of books?

Meanwhile, here are a few steps we can try to smooth things out:

1. Clear Browser Cache and Cookies
Sometimes cached data or cookies can cause display glitches. Since you’re on Windows and using a WebKit browser, you can clear the cache from your browser's settings (usually under Privacy or History). After clearing, reload BookBub and try again.

2. Disable Browser Extensions
Extensions or add-ons related to ad-blocking or script-blocking can interfere with the page layout. Try turning off extensions temporarily to see if that stops the jumping behavior.

3. Try a Different Browser
If possible, try accessing BookBub via a different browser like Chrome, Firefox, or Edge to see if the issue persists. This helps isolate whether the problem is with the specific browser or the app/site itself.

4. Check for Browser Updates
Make sure your WebKit browser is up to date. Older versions can sometimes have rendering issues with modern web apps.

5. Reduce Cart Size Temporarily
If the jumping happens after adding many books, try adding fewer at a time to see if that makes a difference.

If you’ve already tried these, please let me know which steps, and we can explore further options such as checking account or session issues. Also, any details on error messages or other behavior will help.

Are you okay trying these steps now? Let me know how it goes!