I'm trying to build a rather extensive reading plan, and in trying to simplify the process, would like to use the Windows-standard method of selecting a passage of text. I first highlight a couple lines at the start of the text, like this-

Then I scroll down to where the end of the passage will be, and hold down the Shift key and click to select the passage, like this-

I scrolled back to the top to make sure the selection was correct, and it was not. For some reason, a couple words along with a portion of a word preceding the desired selection was highlighted, as here-

This will screw up the reading plan (which is intended to be a public, shared plan). This leaves me with clicking and dragging, which makes finding the end of the passage very difficult. The error is repeatable.
Any help?