Currently there are two ways to highlight text from an imported PDF: using the highlight tool and highlighting freely the document with the aid of a pencil, or manually selecting the text and clicking on the highlight option.
The latter method is more flexible for tasks such as studying on a textbook, as the highlight adjusts in size with the underlying text. Unfortunately, it is a very time consuming approach as it requires to first select the text, wait for a menu popup and then select highlight.
It would be convenient to have an alternate behavior for the highlight tool, such that it only acts on text, reproducing the output of select+highlight, while still being used with a pencil.