It's true, the Content Assistant was refactored. So, now it requires a new nature and a new builder to be specified in .project file of your project. When you create a new project these things are automatically placed there, but for 'old' projects that were imported into workspace (or if you're just using your old workspace) these changes are not performed.
So, please try to do the following changes on .project file of your project:
1. Add the following build command to the 'buildSpec' section of .project file:
<buildSpec> <!-- [Leave unchanged the existing build commands here and add the following command...] --> <buildCommand> <name>org.jboss.tools.jst.web.kb.kbbuilder</name> <arguments> </arguments> </buildCommand> </buildSpec>
2. Add the following nature to the 'natures' section of .project file:
<natures> <!-- [Leave unchanged the existing natures here and add the following nature...] --> <nature>org.jboss.tools.jst.web.kb.kbnature</nature> </natures>
Also, the CA requires the most of tag libraries (TLDs and schemas) to be present at classpath to allow the proposals generation. (But, please, try to perform two steps above first (because they are required to restore CA), then proceed with the libraries checking)
Hope this will help.
Thanks for the explanation - but we really need to find a way to not break existing projects this *hard*.
For the nightly builds its ok (it is the bleeding edge) but we should find a solution - but lets take that discussion on the dev mailing list.