diff --git a/components/codetools/basiccodetools.pas b/components/codetools/basiccodetools.pas
index fa3078d740..973729ea66 100644
--- a/components/codetools/basiccodetools.pas
+++ b/components/codetools/basiccodetools.pas
@@ -1749,7 +1749,7 @@ var FindLen, TxtLen: integer;
 begin
   FindLen:=length(Find);
   TxtLen:=length(Txt);
-  if not CaseSensitive then begin
+  if CaseSensitive then begin
     while (FindStartPos<=FindLen) and (TxtStartPos<=TxtLen) and (Len>0) do begin
       if Find[FindStartPos]=Txt[TxtStartPos] then begin
         inc(FindStartPos);
diff --git a/components/codetools/fileprocs.pas b/components/codetools/fileprocs.pas
index 7c3b0e630b..5fa2389628 100644
--- a/components/codetools/fileprocs.pas
+++ b/components/codetools/fileprocs.pas
@@ -71,17 +71,20 @@ function SearchFileInPath(const Filename, BasePath, SearchPath,
                           Delimiter: string; SearchLoUpCase: boolean): string;
 function FilenameIsMatching(const Mask, Filename: string;
   MatchExactly: boolean): boolean;
-
+function CompareFileExt(const Filename, Ext: string;
+  CaseSensitive: boolean): integer;
 
 implementation
 
-
 // to get more detailed error messages consider the os
 {$IFNDEF win32}
 uses
   {$IFDEF Ver1_0} Linux {$ELSE} Unix {$ENDIF};
 {$ENDIF}
 
+var
+  UpChars: array[char] of char;
+
 function CompareFilenames(const Filename1, Filename2: string): integer;
 begin
   {$IFDEF WIN32}
@@ -626,6 +629,77 @@ begin
   //writeln('  [FilenameIsMatching] Result=',Result,' ',DirStartMask,',',length(Mask),'  ',DirStartFile,',',length(Filename));
 end;
 
+function CompareFileExt(const Filename, Ext: string;
+  CaseSensitive: boolean): integer;
+var
+  FileLen, FilePos, ExtLen, ExtPos: integer;
+  FileChar, ExtChar: char;
+begin
+  FileLen:=length(Filename);
+  ExtLen:=length(Ext);
+  FilePos:=FileLen;
+  while (FilePos>=1) and (Filename[FilePos]<>'.') do dec(FilePos);
+  if FilePos<1 then begin
+    // no extension in filename
+    Result:=1;
+    exit;
+  end;
+  // skip point
+  inc(FilePos);
+  ExtPos:=1;
+  if (ExtPos<=ExtLen) and (Ext[1]='.') then inc(ExtPos);
+  // compare extensions
+  while true do begin
+    if FilePos<=FileLen then begin
+      if ExtPos<=ExtLen then begin
+        FileChar:=Filename[FilePos];
+        ExtChar:=Ext[ExtPos];
+        if not CaseSensitive then begin
+          FileChar:=UpChars[FileChar];
+          ExtChar:=UpChars[ExtChar];
+        end;
+        if FileChar=ExtChar then begin
+          inc(FilePos);
+          inc(ExtPos);
+        end else if FileChar>ExtChar then begin
+          Result:=1;
+          exit;
+        end else begin
+          Result:=-1;
+          exit;
+        end;
+      end else begin
+        // fileext longer than ext
+        Result:=1;
+        exit;
+      end;
+    end else begin
+      if ExtPos<=ExtLen then begin
+        // fileext shorter than ext
+        Result:=-1;
+        exit;
+      end else begin
+        // equal
+        Result:=0;
+        exit;
+      end;
+    end;
+  end;
+end;
+
+
+procedure InternalInit;
+var
+  c: char;
+begin
+  for c:=Low(char) to High(char) do begin
+    UpChars[c]:=upcase(c);
+  end;
+end;
+
+initialization
+  InternalInit;
+
 
 end.
 
diff --git a/components/codetools/finddeclarationtool.pas b/components/codetools/finddeclarationtool.pas
index 04b7af1797..5b49ee30c9 100644
--- a/components/codetools/finddeclarationtool.pas
+++ b/components/codetools/finddeclarationtool.pas
@@ -1029,8 +1029,8 @@ function TFindDeclarationTool.FindUnitSource(const AnUnitName,
         {$IFDEF ShowTriedFiles}
         //writeln('  unit "',copy(UnitLinks,UnitLinkStart,UnitLinkEnd-UnitLinkStart),'"');
         {$ENDIF}
-        if AnsiCompareText(TheUnitName,
-                     copy(UnitLinks,UnitLinkStart,UnitLinkEnd-UnitLinkStart))=0
+        if CompareSubStrings(TheUnitName,UnitLinks,1,
+          UnitLinkStart,UnitLinkEnd-UnitLinkStart,false)=0
         then begin
           // unit found -> parse filename
           UnitLinkStart:=UnitLinkEnd+1;
@@ -1041,6 +1041,13 @@ function TFindDeclarationTool.FindUnitSource(const AnUnitName,
           if UnitLinkEnd>UnitLinkStart then begin
             CurFilename:=copy(UnitLinks,UnitLinkStart,UnitLinkEnd-UnitLinkStart);
             LoadFile(CurFilename,Result);
+            if Result=nil then begin
+              // try also different extensions
+              if CompareFileExt(CurFilename,'.pp',false)=0 then
+                LoadFile(ChangeFileExt(CurFilename,'.pas'),Result)
+              else
+                LoadFile(ChangeFileExt(CurFilename,'.pp'),Result);
+            end;
             exit;
           end;
         end else begin
@@ -2998,6 +3005,7 @@ begin
     ReadNextAtom;
     ReadNextAtom;
     if (Scanner.PascalCompiler<>pcDelphi)
+    and Scanner.InitialValues.IsDefined('VER1_0')
     and Scanner.InitialValues.IsDefined('LINUX')
     then
       // ToDo: other OS than linux