Highlighting PDFs are one of the most frustrating aspects of using the edge. It seems like most academic papers are formatted so you can't select a single word. I've also constantly run into serious problems where trying to highlight something will cause my EE to freeze up for several minutes. Tech support said it's a problem with the way Adobe Acrobat presents data to them so there wasn't much they could do beyond filing a bug report with Adobe.

I hope they can improve this in the future because I am not keen on using underlines instead of highlighting.