Which product are you using?
PDF.js Express Viewer PDF.js Express Version
8.7.1 Detailed description of issue
Is it possibly to have the page scrolling when the text selection is active, meaning when the user reaches the bottom of the page with the cursor scrolling should happen automatically.
When the user reaches the bottom of the page with the cursor a scrolling action should be done until the user releases the left mouse button and the text selection is completed. The aim is to select text on multiple consecutive pages.
Does your issue happen with every document, or just one?