I also have trouble adding a bookmark.... :(
It is a small 2" box ...the buttons at the top that normally would minimize, full screen or close.. the only ones that work are minimize and close. Full screen doesn't work so you can't see where the part is to add the bookmark. Sometimes I can highlight, which will let me scroll down on it to add a bookmark
but this is a hassel and can't always get it to work that way. I have tried putting my cursor over the box and hitting enter on my keyboard as suggested but that doesn't do anything. Any help please? Thank you