You're right, same problem.
For me (using Chrome in either OSX or Windows7) when the dialog box opens after clicking the insert-image icon, "http://" is already selected, so if I just paste into the dialog box that opened without clicking anything, it inserts the URL I've already selected in place of the preset text in the dialog box.
Zero Gravitas — 2017 Flying Cloud 26U | Il Progetto — 1976 Argosy 28 Center Bath | WBCCI# 15566
He has all of the virtues I dislike and none of the vices I admire. — Sir Winston Churchill