SQL Developer "disconnected from the rest of the join graph"

I got this as well. I'm not exactly sure how to articulate it but the error seems to be based on the logical flow of the code.

Essentially because you mention the table pluspbillline before workorder I think it expects the join to be on pluspbillline.siteid=workorder.siteid etc.

It seems that the order of the conditions for joins should flow from the first identified tables to the latest ones. So the following should make it happy:

plusbillline to workorder       on pluspbillline.siteid=workorder.siteid...
    ""       to ticket          on pluspbillline.ticketid = ticket.ticketid...
    ""       to pluspsalesorder on pluspbillline.salesordernum = pluspsalesorder.salesordernum...

I don't believe this would change the work oracle does (assuming you don't use optimizer hints) so I'd only bother to change if you hate the squiggly lines.