new user to endnote: A new reference box is opening to add notes from a pdf I

Endnote x7.5.3

When I open the reference list. I used to be able to double click on a reference and the PDF and reference box would open up side by side, so that I could copy and paste information straight into the reference tab

Now the reference tab opens up as a seperate screen and it dissapears each time i click on the PDF to copy and paste information?

Is there a way of returning to the original experience, where I clicked on the reference screen and then a new screen would open which had both a reference and PDF side by side?

Kind Regards,