Hi Haukur!

"Þetta þótti mörgum manni vanhagr mikill,
sem var, at sitja um þat fram er markaðrinn stóð."

Does that help?

Yes, a bit, as it shows me that it's centred on the nature of the vanhagr, but I'm afraid I'm still confused about the exact sense.

I've got the feeling of hitting all round it without quite getting to it, having just discovered the flwg:

um (at a point of time)
um þat = at that time, then
um þat er = when

but what about um þat fram er, please?

Cheers,

Simon