I noticed that existing transition lines show up if I switch the positions of the 'name' and 'to' attributes, for example:
<transition name="to_state" to="first"> to: <transition to="first" name="to_state">
(I would think the GPD should be able to accept both versions though, so you may want to file a bug report for this)
Hmmm... I think you're right that it's related to schema changes, but just making the to/name exchange didn't fix it for me.
If I make new diagrams, they work ok - it's only the examples (including the "simple" one optionally created in every project) that don't show transitions. I see that gpd.xml is structured quite differently in alpha4, but trying to clone what I saw in "good" ones didn't help either.
I suspect that the problem arises, in part, because the examples are not in the GPD source tree.
I'll JIRA this.
Ed, I switched the order of the attributes because that's how new (and visible) transitions get added. Changing the order in the first transition in 'simple' did it for me, while it's quite possible this may not always work.
BTW, I'm running HEAD, as opposed to alpha4, if that makes any difference (but regardless this sounds like a bug)
same happens here. Drawing new transitions works though. I think that changing the order somehow triggers the gpd to redraw. There are other small issues as well... the forms.xml and forms pages do not get deployed.
Sorry for chiming in that late. There is an incompatibility in the gpd.xml when upgrading from GPD 3.0.x to 3.1.x. Just find/replace 'process-diagram' with 'root-container' and 'transition' with 'edge' in the gpd.xml and it will be okay. I will provide an automatic conversion in the final release.