Attaching a screencast to demonstrate the problem. Running F19 with GTK+ 3.8.2; this has been much the same ever since the Owncloud integration showed up.

So I use GNOME 3.8's Owncloud integration to set up my account. This makes a "adamw@(owncloudurl)" entry with an icon that looks like a computer show up in the sidebar of the file chooser. Nifty! But when I go to use it, the behaviour is kind of bizarre: I click on it and a _new_ entry is create. This one has the 'remote folder' icon, and is named slightly differently: "adamw on (owncloud host)". I have to click on that one to actually access the remote share.

At each boot, there will just be the "adamw@(owncloudurl)" entry. Once you click on it and the "adamw on (owncloud host)" entry shows up, both entries will be present in file chooser dialogs for the rest of that session; clicking the "adamw@(owncloudurl)" entry basically does nothing, clicking the "adamw on (owncloud host)" entry works.