Fix copy-to-clipboard functionality

[tstirrat15]

Clicking on a highlight and then clicking the little Link icon doesn't copy the share link to my clipboard, at least on my computer.

[ivanauth]

@tstirrat15 Copy-to-clipboard works for me in both Chrome and Safari. Which browser are you using?

[tstirrat15]

Firefox. It may be related to that - I'll dig into it.