diff --git a/platform/platform-impl/src/com/intellij/openapi/fileTypes/impl/FileTypeManagerImpl.java b/platform/platform-impl/src/com/intellij/openapi/fileTypes/impl/FileTypeManagerImpl.java
index 03880b8fd2b4..bbe868feffdd 100644
--- a/platform/platform-impl/src/com/intellij/openapi/fileTypes/impl/FileTypeManagerImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/fileTypes/impl/FileTypeManagerImpl.java
@@ -1092,7 +1092,7 @@ public class FileTypeManagerImpl extends FileTypeManagerEx implements Persistent
 
   @Override
   public boolean isFileOfType(@NotNull VirtualFile file, @NotNull FileType type) {
-    if (type instanceof PlainTextLikeFileType || type.equals(UnknownFileType.INSTANCE)) {
+    if (mightBeReplacedByDetectedFileType(type) || type.equals(UnknownFileType.INSTANCE)) {
       // a file has unknown file type if none of file type detectors matched it
       // for plain text file type, we run file type detection based on content