diff --git a/src/main/java/de/platon42/intellij/plugins/m68k/M68kFileElementType.kt b/src/main/java/de/platon42/intellij/plugins/m68k/M68kFileElementType.kt
index 98df13d..cb586b7 100644
--- a/src/main/java/de/platon42/intellij/plugins/m68k/M68kFileElementType.kt
+++ b/src/main/java/de/platon42/intellij/plugins/m68k/M68kFileElementType.kt
@@ -1,28 +1,21 @@
 package de.platon42.intellij.plugins.m68k
 
-import com.intellij.psi.PsiFile
-import com.intellij.psi.stubs.DefaultStubBuilder
-import com.intellij.psi.stubs.StubElement
-import com.intellij.psi.tree.IStubFileElementType
+import com.intellij.psi.stubs.PsiFileStub
+import com.intellij.psi.tree.ILightStubFileElementType
 import de.platon42.intellij.plugins.m68k.psi.M68kFile
-import de.platon42.intellij.plugins.m68k.stubs.M68kFileStub
 
-class M68kFileElementType private constructor() : IStubFileElementType<M68kFileStub>("MC68000_FILE", MC68000Language.INSTANCE) {
+class M68kFileElementType private constructor() : ILightStubFileElementType<PsiFileStub<M68kFile>>("MC68000_FILE", MC68000Language.INSTANCE) {
 
     companion object {
         @JvmField
         val INSTANCE = M68kFileElementType()
 
-        const val STUB_VERSION = 2
+        const val STUB_VERSION = 3
         const val STUB_EXTERNAL_ID_PREFIX = "MC68000."
+        const val EXTERNAL_ID = STUB_EXTERNAL_ID_PREFIX + "FILE"
     }
 
     override fun getStubVersion() = STUB_VERSION
 
-    override fun getBuilder() =
-        object : DefaultStubBuilder() {
-            override fun createStubForFile(file: PsiFile): StubElement<*> {
-                return if (file is M68kFile) M68kFileStub(file) else super.createStubForFile(file)
-            }
-        }
+    override fun getExternalId() = EXTERNAL_ID
 }
\ No newline at end of file
diff --git a/src/main/java/de/platon42/intellij/plugins/m68k/stubs/M68kFileStub.kt b/src/main/java/de/platon42/intellij/plugins/m68k/stubs/M68kFileStub.kt
index 9e56581..a50c447 100644
--- a/src/main/java/de/platon42/intellij/plugins/m68k/stubs/M68kFileStub.kt
+++ b/src/main/java/de/platon42/intellij/plugins/m68k/stubs/M68kFileStub.kt
@@ -3,4 +3,4 @@ package de.platon42.intellij.plugins.m68k.stubs
 import com.intellij.psi.stubs.PsiFileStubImpl
 import de.platon42.intellij.plugins.m68k.psi.M68kFile
 
-class M68kFileStub(file: M68kFile?) : PsiFileStubImpl<M68kFile?>(file)
\ No newline at end of file
+class M68kFileStub(file: M68kFile) : PsiFileStubImpl<M68kFile>(file)
\ No newline at end of file
diff --git a/src/main/java/de/platon42/intellij/plugins/m68k/stubs/M68kStubElementTypeFactory.kt b/src/main/java/de/platon42/intellij/plugins/m68k/stubs/M68kStubElementTypeFactory.kt
index ba30d8d..0438443 100644
--- a/src/main/java/de/platon42/intellij/plugins/m68k/stubs/M68kStubElementTypeFactory.kt
+++ b/src/main/java/de/platon42/intellij/plugins/m68k/stubs/M68kStubElementTypeFactory.kt
@@ -7,9 +7,9 @@ import de.platon42.intellij.plugins.m68k.psi.M68kPsiElement
 object M68kStubElementTypeFactory {
     @JvmStatic
     fun stubFactory(name: String): IStubElementType<out StubElement<out M68kPsiElement>, out M68kPsiElement> {
-        when (name) {
-            "GLOBAL_LABEL" -> return M68kElementTypes.GLOBAL_LABEL
-            "SYMBOL_DEFINITION" -> return M68kElementTypes.SYMBOL_DEFINITION
+        return when (name) {
+            "GLOBAL_LABEL" -> M68kElementTypes.GLOBAL_LABEL
+            "SYMBOL_DEFINITION" -> M68kElementTypes.SYMBOL_DEFINITION
             else -> throw RuntimeException("Unknown element type '$name'")
         }
     }