Is there a way to display the full text of a lesson in a single editing box instead of having several hundred editing boxes, one for each line of each paragraph?

I've imported a book where the first third of it is just background on the author and I'd like to remove that.

Yes, I can edit externally before importing, but it would be convenient if I could simply highlight and delete the portion of the text directly and quickly in the editor post-importation.

Currently, to do this in Lingq I'd have to individually click on each line's text box, then hit the delete button. That is very time consuming. Unless there is a setting or a button I'm missing to do this more quickly?