I have an artifact defined with a pre-processing ant task that uses an input task to ask the user for a parameter. This is apparently causing the build process to completely lock up. everything looks like it is running but the statusbar just says "building artifact myArtifact:war exploded" and sits and spins. When I remove the pre-processor, the artifact compiles and builds. I can run the pre-processor just fine from the ant build window separately and it will pop up a dialog for entering the parameter.
This was working in 10.5.4 and I just upgraded today.