Add ability to scroll text view while highlighting text

**Is your feature request related to a problem? Please describe (REQUIRED):**

Scrolling the text view up and down doesn't work while highlighting text.

**Describe the solution you'd like (REQUIRED):**

I would like to be able to precisely highlight the text that I want to delete, rather than having to push my mouse up or down, which ends up scrolling the text view way too far.

**Describe alternatives you've considered (REQUIRED):**

Repeatedly hitting alternative keys to scroll bits at a time, or pushing the mouse around, both of which cause frustration and waste time.

**Additional context (OPTIONAL):**

The following screenshot shows trying to highlight more of the function above the highlighted section, but being unable to quickly and precisely do so.