diff --git a/ide/ideprocs.pp b/ide/ideprocs.pp
index 10aac77862..baa697f6f0 100644
--- a/ide/ideprocs.pp
+++ b/ide/ideprocs.pp
@@ -330,7 +330,7 @@ end;
   function FindFilesCaseInsensitive(const Directory,
     CaseInsensitiveFilename: string; IgnoreExact: boolean): TStringLists;
 
-  Search case insensitive in Directory for all files
+  Search Pascal case insensitive in Directory for all files
   named CaseInsensitiveFilename
 -------------------------------------------------------------------------------}
 function FindFilesCaseInsensitive(const Directory,
@@ -346,7 +346,7 @@ begin
       // check if special file
       if (FileInfo.Name='.') or (FileInfo.Name='..') or (FileInfo.Name='') then
         continue;
-      if (CompareFilenamesIgnoreCase(CaseInsensitiveFilename,FileInfo.Name)=0)
+      if (CompareText(CaseInsensitiveFilename,FileInfo.Name)=0) // Pascal insensitibity, not UTF-8, thing about Turkish I
       and ((not IgnoreExact)
            or (CompareFilenames(CaseInsensitiveFilename,FileInfo.Name)<>0))
       then begin
diff --git a/ide/project.pp b/ide/project.pp
index 1bacc32e67..e285cb8092 100644
--- a/ide/project.pp
+++ b/ide/project.pp
@@ -5546,8 +5546,8 @@ var
       AFileName:=ExtractFilename(AFileName);
     if siffCaseSensitive in SearchFlags then
       Result:=SearchedFilename=AFilename
-    else
-      Result:=CompareFilenamesIgnoreCase(SearchedFilename,AFilename)=0;
+    else // check Pascal case insensitivity (CompareText, do not use CompareFilenamesIgnoreCase, because of Turkish I)
+      Result:=CompareText(SearchedFilename,AFilename)=0;
   end;
   
 begin