Okay, here is one of those sort of annoying things that makes me wonder "is there a better way?".
The "add image" click brings up an overlay in the browser to input an image. Now, often I am linking images, and also trying to remember the name of the image. So I will copy and paste the name of the image, click to another browser window to go get the link, come back, and add the link into that dialog.
The problem comes if you happen to click outside of the overlay area. The overlay disappears, and all the information in it is lost - no way to get it back. Is there no way to lock the focus on that layer until completed?