Before entering savngarde portal there was something called dragon seal that had an activate icon but didnt seem to do anything. Was it glitched or was I missing something to allow me to use it?

Given how the objects are set up in the editor, there is no room for "glitches" like this. However, does it have a use or not, I can not say.

It shows the activate option because it was set up as an activator. So my guess would be there is something that can activate it.

There is an object needed to unlock the portal. Further along the questline you will go up there and see this in use by something.

You sure we are talking about the same thing? I thought you could only go there once. I just killed the shade and walked into the portal. I dont think I looted anything off him. And the quest is done now because alduin is dead.

edit: In fact in my previous run through I just ran past the shade and jumped in so Im sure I didnt activate the dragon seal.

The seal starts out open. The Dragon priest walks up and grabs the key (staff). If you kill him real fast (recomended), you don't need to open it manually because it is already open.

The dragon priest has a staff which unlocks the portal. I killed the priest while he was still doing his thing with the portal and took the staff and the portal closed. I haven't gone into sovengard yet but i have the staff and it does open the portal for you when you place it in the slot.