oops, this time PDE's warning was right, fixed.
diff --git a/plugins/org.eclipse.objectteams.otdt.debug.ui/build.properties b/plugins/org.eclipse.objectteams.otdt.debug.ui/build.properties
index f5dec46..c953237 100644
--- a/plugins/org.eclipse.objectteams.otdt.debug.ui/build.properties
+++ b/plugins/org.eclipse.objectteams.otdt.debug.ui/build.properties
@@ -6,4 +6,5 @@
                icons/,\
                plugin.properties,\
                about.html
+javacProjectSettings = true