Marking text in notes sometimes skip to next slide

When i use my mouse to mark text while editing the presenter notes, and drag the mouse all the way to the left (to mark everything quickly), it skips to the next slide and takes the notes with it?? 
So suddenly i am at the next slide with the notes i just wrote for the previous slide. And then when I go back to the previous slide, the notes section is blank, and I have to cut and paste it back to the correct slide.

This is very annoying, and breaks my work flow each time it happens.