diff --git a/ide/environmentopts.pp b/ide/environmentopts.pp
index d433d64a2a..19e24e50c7 100644
--- a/ide/environmentopts.pp
+++ b/ide/environmentopts.pp
@@ -2299,8 +2299,7 @@ begin
   CurLazDir:=ChompPathDelim(LazarusDirectory);
   if not TTransferMacroList.StrHasMacros(CurLazDir) then begin
     BaseDir:=ExtractFilePath(ChompPathDelim(GetPrimaryConfigPath));
-    if (CompareFilenames(BaseDir,CurLazDir)=0)
-    or FileIsInPath(CurLazDir,BaseDir) then begin
+    if PathIsInPath(CurLazDir,BaseDir) then begin
       // the pcp directory is in the lazarus directory
       // or the lazarus directory is a sibling or a sub dir of a sibling of the pcp
       // examples:
diff --git a/ide/ideprocs.pp b/ide/ideprocs.pp
index dead3972f4..814293027d 100644
--- a/ide/ideprocs.pp
+++ b/ide/ideprocs.pp
@@ -50,6 +50,7 @@ function CreateEmptyFile(const Filename: string): boolean;
 function FilenameIsPascalSource(const Filename: string): boolean;
 function ChompEndNumber(const s: string): string;
 function ShortDisplayFilename(const aFileName: string): string;
+function PathIsInPath(const Path, Directory: string): boolean;
 
 // find file
 function FindFilesCaseInsensitive(const Directory,
@@ -505,10 +506,7 @@ function GetNextUsedDirectoryInSearchPath(const SearchPath,
 begin
   while (NextStartPos<=length(SearchPath)) do begin
     Result:=GetNextDirectoryInSearchPath(SearchPath,NextStartPos);
-    if (Result<>'')
-    and ((CompareFilenames(Result,FilterDir)=0)
-      or FileIsInPath(Result,FilterDir))
-    then
+    if (Result<>'') and PathIsInPath(Result,FilterDir) then
       exit;
   end;
   Result:=''
@@ -723,6 +721,20 @@ begin
     Result := aFileName;
 end;
 
+function PathIsInPath(const Path, Directory: string): boolean;
+var
+  ExpPath: String;
+  ExpDir: String;
+  l: integer;
+begin
+  if Path='' then exit(false);
+  ExpPath:=AppendPathDelim(ResolveDots(Path));
+  ExpDir:=AppendPathDelim(ResolveDots(Directory));
+  l:=length(ExpDir);
+  Result:=(l>0) and (length(ExpPath)>=l) and (ExpPath[l]=PathDelim)
+          and (CompareFilenames(ExpDir,LeftStr(ExpPath,l))=0);
+end;
+
 function FindFirstFileWithExt(const Directory, Ext: string): string;
 var
   FileInfo: TSearchRec;
diff --git a/ide/main.pp b/ide/main.pp
index f0a872900e..825279b66d 100644
--- a/ide/main.pp
+++ b/ide/main.pp
@@ -1409,7 +1409,7 @@ begin
   and (CheckFPCExeQuality(EnvironmentOptions.GetParsedCompilerFilename,Note,
                        CodeToolBoss.CompilerDefinesCache.TestFilename)=sddqInvalid)
   then begin
-    debugln(['Warning: (lazarus) invalid compiler: ',EnvironmentOptions.GetParsedCompilerFilename]);
+    debugln(['Warning: (lazarus) invalid compiler: ',EnvironmentOptions.GetParsedCompilerFilename,' ',Note]);
     ShowSetupDialog:=true;
   end;
 
@@ -1421,7 +1421,7 @@ begin
     if CheckFPCSrcDirQuality(EnvironmentOptions.GetParsedFPCSourceDirectory,Note,
       CfgCache.GetFPCVer)=sddqInvalid
     then begin
-      debugln(['Warning: (lazarus) invalid fpc source directory: ',EnvironmentOptions.GetParsedFPCSourceDirectory]);
+      debugln(['Warning: (lazarus) invalid fpc source directory: ',EnvironmentOptions.GetParsedFPCSourceDirectory,' ',Note]);
       ShowSetupDialog:=true;
     end;
   end;
@@ -6763,7 +6763,7 @@ begin
         UnitOutputDirectory:=TrimFilename(WorkingDir+PathDelim+UnitOutputDirectory);
       if FilenameIsAbsolute(UnitOutputDirectory) then begin
         if (not DirPathExistsCached(UnitOutputDirectory)) then begin
-          if not FileIsInPath(UnitOutputDirectory,WorkingDir) then begin
+          if not PathIsInPath(UnitOutputDirectory,WorkingDir) then begin
             Result:=IDEQuestionDialog(lisCreateDirectory,
                 Format(lisTheOutputDirectoryIsMissing, [UnitOutputDirectory]),
                 mtConfirmation, [mrYes, lisCreateIt,
@@ -6777,7 +6777,8 @@ begin
           end;
         end;
         if Project1.IsVirtual
-        and (FileIsInPath(UnitOutputDirectory,EnvironmentOptions.GetParsedTestBuildDirectory))
+        and (PathIsInPath(UnitOutputDirectory,
+                          EnvironmentOptions.GetParsedTestBuildDirectory))
         then begin
           // clean up test units
           Result:=CleanUpTestUnitOutputDir(UnitOutputDirectory);
@@ -6799,7 +6800,7 @@ begin
             if Result<>mrIgnore then exit(mrCancel);
           end;
         end else begin
-          if not FileIsInPath(AppendPathDelim(TargetExeDirectory)+'dummy',WorkingDir)
+          if not PathIsInPath(TargetExeDirectory,WorkingDir)
           then begin
             Result:=IDEQuestionDialog(lisCreateDirectory,
                 Format(lisTheOutputDirectoryIsMissing, [TargetExeDirectory]),
@@ -11734,12 +11735,12 @@ begin
     SaveDialog.FileName:=SaveAsFilename;
     // if this is a project file, start in project directory
     if AnUnitInfo.IsPartOfProject and (not Project1.IsVirtual)
-    and (not FileIsInPath(SaveDialog.InitialDir,Project1.Directory)) then
+    and (not PathIsInPath(SaveDialog.InitialDir,Project1.Directory)) then
       SaveDialog.InitialDir:=Project1.Directory;
     // if this is a package file, then start in package directory
     PkgDefaultDirectory:=PkgBoss.GetDefaultSaveDirectoryForFile(AnUnitInfo.Filename);
     if (PkgDefaultDirectory<>'')
-    and (not FileIsInPath(SaveDialog.InitialDir,PkgDefaultDirectory)) then
+    and (not PathIsInPath(SaveDialog.InitialDir,PkgDefaultDirectory)) then
       SaveDialog.InitialDir:=PkgDefaultDirectory;
     // show save dialog
     if (not SaveDialog.Execute) or (ExtractFileName(SaveDialog.Filename)='') then
diff --git a/ide/sourcefilemanager.pas b/ide/sourcefilemanager.pas
index aec618e946..f487b7f058 100644
--- a/ide/sourcefilemanager.pas
+++ b/ide/sourcefilemanager.pas
@@ -4602,13 +4602,13 @@ begin
     // if this is a project file, start in project directory
     if (AnUnitInfo=nil)
     or (AnUnitInfo.IsPartOfProject and (not Project1.IsVirtual)
-        and (not FileIsInPath(SaveDialog.InitialDir,Project1.Directory)))
+        and (not PathIsInPath(SaveDialog.InitialDir,Project1.Directory)))
     then begin
       SaveDialog.InitialDir:=Project1.Directory;
     end;
     // if this is a package file, then start in package directory
     APath:=PkgBoss.GetDefaultSaveDirectoryForFile(AFilename);
-    if (APath<>'') and (not FileIsInPath(SaveDialog.InitialDir,APath)) then
+    if (APath<>'') and (not PathIsInPath(SaveDialog.InitialDir,APath)) then
       SaveDialog.InitialDir:=APath;
 
     repeat
@@ -5382,7 +5382,7 @@ begin
         OldLRSFilePath:=ExtractFilePath(LRSCode.Filename);
         NewLRSFilePath:=OldLRSFilePath;
         if FilenameIsAbsolute(OldFilePath)
-        and FileIsInPath(OldLRSFilePath,OldFilePath) then begin
+        and PathIsInPath(OldLRSFilePath,OldFilePath) then begin
           // resource code was in the same or in a sub directory of source
           // -> try to keep this relationship
           NewLRSFilePath:=NewFilePath