--- a/ProjectDefinition.st	Tue Aug 20 15:14:41 2019 +0200
+++ b/ProjectDefinition.st	Tue Aug 20 15:15:09 2019 +0200
@@ -1457,7 +1457,7 @@
     prerequisiteList keysDo:[:eachPackageSymbol|
         |defClass|
 
-        defClass := self definitionClassForPackage:eachPackageSymbol.
+        defClass := (self definitionClassForPackage:eachPackageSymbol) theNonMetaclass.
         (defClass isProjectDefinition and:[defClass isPluginDefinition]) ifTrue:[
             (self confirm:('Bad cross-plugin requirement to: %1%<cr>%<cr>Proceed?' bindWith:eachPackageSymbol)) ifFalse:[
                 AbortOperationRequest raiseRequest.