behaviour of notes in preview el capitan

Dear All,

This is a minor matter, but I wondered if anyone had a fix for it nevertheless.

I use Preview frequently, and often use its Notes feature to mark up screenplays. Recently the notes have started to blink, or perhaps even open twice in quick succession, when I click on them. I'm referring to the notes embedded in the text page, rather than in the sidebar.

I wonder if this is a fixable bug, or even one that anyone else has experienced? It's not disastrous, obviously, but it doesn't conform to the smoothly-functioning graphic standards you'd hope for.

Thanks in advance,

Roger