diff --git a/src/org/geometerplus/fbreader/book/BookCollection.java b/src/org/geometerplus/fbreader/book/BookCollection.java
index 5823acdae..322aa4ecc 100644
--- a/src/org/geometerplus/fbreader/book/BookCollection.java
+++ b/src/org/geometerplus/fbreader/book/BookCollection.java
@@ -69,7 +69,7 @@ public class BookCollection extends AbstractBookCollection {
 		if (plugin == null) {
 			return null;
 		}
-		if (!plugin.type().Builtin && bookFile != bookFile.getPhysicalFile()) {
+		if (!(plugin instanceof BuiltinFormatPlugin) && bookFile != bookFile.getPhysicalFile()) {
 			return null;
 		}
 		try {
diff --git a/src/org/geometerplus/fbreader/formats/FormatPlugin.java b/src/org/geometerplus/fbreader/formats/FormatPlugin.java
index ef40940ef..f171941a7 100644
--- a/src/org/geometerplus/fbreader/formats/FormatPlugin.java
+++ b/src/org/geometerplus/fbreader/formats/FormatPlugin.java
@@ -54,18 +54,11 @@ public abstract class FormatPlugin {
 	public abstract String readAnnotation(ZLFile file);
 
 	public enum Type {
-		ANY(false),
-		JAVA(true),
-		NATIVE(true),
-		EXTERNAL(false),
-		EXTERNAL_PROGRAM(false),
-		NONE(false);
-
-		public final boolean Builtin;
-
-		Type(boolean builtin) {
-			Builtin = builtin;
-		}
+		ANY,
+		JAVA,
+		NATIVE,
+		EXTERNAL,
+		EXTERNAL_PROGRAM;
 	};
 	public abstract Type type();
 
diff --git a/src/org/geometerplus/fbreader/formats/PluginCollection.java b/src/org/geometerplus/fbreader/formats/PluginCollection.java
index 3b340ef0e..115f11c78 100644
--- a/src/org/geometerplus/fbreader/formats/PluginCollection.java
+++ b/src/org/geometerplus/fbreader/formats/PluginCollection.java
@@ -88,8 +88,6 @@ public class PluginCollection {
 		}
 
 		switch (formatType) {
-			case NONE:
-				return null;
 			case ANY:
 			{
 				FormatPlugin p = getPlugin(fileType, FormatPlugin.Type.NATIVE);