[UI] Checkbox "Extract each page into separate document" - should be disabled by default

[ciur]

Scenario: two document viewer should be opened side by side (left and right panels)
In document viewer on one side, select couple of pages (in thumbnails panel) and then from the context menu click "extract".

Following dialog appears:

Currently the checkbox is "checked by default" which means, that if user selects more then one page, he or she can unwillingly extract e.g. 10 pages as 10 separate documents.
It would be nice have "extract each page into separate document" checkbox to be "unchecked" by default.

Also, it would be nice that when user "checks", there will be a message saying something like "this action will create 10 separate documents" or maybe when user "checks" rename the button from "yes" to "Extract as 10 separate documents"?