My best guess would be that it needs more light than what its currently getting. What direction does that window face? I don't own a Marginata, but the Dracaenas that I do have, they all receive very bright, indirect sunlight all day long.

I have several Ponytail Palms (yeah, I know they're a completely different type of plant. I'm just referencing it as an example...) and if/when they don't receive enough sunlight, their leaves will droop and look saggy, too. Well, their newer leaves will. Once again, that's a different type of plant with different growing conditions. But the reason is the same, if they don't get sufficient energy from their light sources, then they won't be perky and erect like they should be.

It's currently in front of a window facing South and about 5 ft away from a window facing West.

It's currently in front of a window facing South and about 5 ft away from a window facing West.