Unreliable display of named image frames via EDD

Hi all,

I have formatted my <prolog> element to display named images frames from the reference page above and below. The intention is to distinguish this area for the editor.

However, the lower frame is displayed very unreliable. For example, if I insert a <keywords> element with a single <kexword> child element then it is not displayed. As soon as I add another <keyword> child the line appears. But if I delete this second <keyword>, the line stays visible the way it should have been from begin with. After saving and reloading it usually is not visible either, moving the elements in the prolog around a bit makes the lower line visible again.

I could not get this to work reliable, does anybody have a recommendation?

Robert