Your page no longer jumps when the assistant panel opens

When the assistant panel opens with a dimmed backdrop (or on a narrow screen, where it fills the display), it stops the page behind it from scrolling. On Windows and Linux desktop that also removed the page's scrollbar, and everything horizontally centred on your storefront slid about 15 pixels sideways for as long as the panel was open, then slid back when it closed.

The panel now reserves the space the scrollbar was taking, so your content doesn't move: not when the panel opens, and not when it closes. If your storefront already sets its own right-hand spacing, that spacing is preserved rather than replaced.

Nothing to change on your side. Nothing was affected on macOS or on phones and tablets, where the scrollbar floats over the page instead of taking space from it, and nothing was affected in the default desktop setup, where the panel sits alongside your page and never locks scrolling.

One case remains: an element you've pinned to the right edge of the screen (a back-to-top button, a sticky sidebar) still moves by the scrollbar's width while the panel is open. Fixing that would mean changing your own stylesheet, so we're flagging it rather than silently working around it.