Users want the ability to highlight text and copy-to-clipboard while in Preview mode.
Currently, clicking and dragging results in entering comment-generation mode.
The only workarounds:
1. Enter editing mode (but this may not be possible with all roles, and may risk making unintended changes)
2. View the document full-screen (this is not intuitive).

Solution: add a one-click toggle, perhaps on the comment/annotation floating panel, that enables click-and-drag commenting OR disables it so highlight-and-copy can be used.

This also could be implemented in such a way as to fulfill the following request
https://pulse.box.com/forums/909778-help-shape-the-future-of-box/suggestions/43240458-ability-to-turn-off-comment-function