In the site editor, under Pages, the data views component defaults to a new format, "List View", which shows a side by side of pages list on the left, and a preview for each page on the right.

The frame on the right has a resize handle. In most contexts, when you scale up the frame, you enter the fullscreen editor. You can also scale this down to preview tablet and mobile sizes:

When scaling down the frame, we should consider to improve the ergonomics of the list view display by resizing that view as well, to take advantage of the wider space. So, by resizing using this handle in the List view, we can go from the default state—

—to a resized state where the list itself is wider, and the preview is less wide:

The above is an inspector-hacked mockup mainly to get the point across. Note how the list view/center column is wider, and the resize handle sits in the gutter between list view and preview frame.

To clarify:

• In the default view, the resize handle resizes the preview just as it does today.
• In the split view (List view), the resizing is different, it simply makes the list column wider. The preview on the right keeps its right side position.
• In this split view, hovering the frame with the cursor should not scale up the frame.

See also:

• Site view: Resize handle does not allow scaling up to snap to fullscreen editor #62746

Related:

• Preview frame animation should only trigger when hovering the frame #52175
• Focus mode and edit site resize handles should be the same #52652