Cross-page text selection fails when paragraph spans multiple pages (split blocks)

[blyzmaksim]

Type

• Bug

Description

When using pagination mode, text selection via click-and-drag works correctly between distinct paragraphs on different pages, but fails when trying to select across a split block (a single paragraph that spans two pages).

Current Behavior

• The selection sticks at the bottom of Page 2
• The highlight does not extend into Page 3
• Auto-scroll during drag does not trigger because the selection position has not changed

Note: Selection works correctly between distinct paragraphs on different pages.
The issue only occurs with split blocks (a single paragraph spanning two pages).

Expected Behavior

• The text selection should smoothly extend from Page 2 into Page 3
• All text in the drag path should be highlighted
• Auto-scrolling should occur if necessary

Steps to Reproduce

1. Initialize SuperDoc with pagination: true
2. Create or open a document with a long paragraph that naturally spans from Page 2 to Page 3
3. Click at the beginning of that paragraph on Page 2
4. Hold the mouse button and drag downward to select text
5. Continue dragging across the page break into Page 3

SuperDoc Version

1.3

Browser & Version

Chrome 120

OS

MacOS 15.5

Additional Context

This issue also appears on the Superdocs website demo!

Checklist

• Tested with latest version
• Checked for duplicates
• Added relevant labels

[linear]

IT-266