diff --git a/ide/mainintf.pas b/ide/mainintf.pas
index fdd4283325..0658e8b36f 100644
--- a/ide/mainintf.pas
+++ b/ide/mainintf.pas
@@ -158,10 +158,6 @@ type
     function DoPublishModule(Options: TPublishModuleOptions;
                              const SrcDirectory, DestDirectory: string
                              ): TModalResult; virtual; abstract;
-
-    function ExtendProjectUnitSearchPath(AProject: TProject; NewUnitPaths: string): boolean;
-    function ExtendProjectIncSearchPath(AProject: TProject; NewIncPaths: string): boolean;
-
     function DoFixupComponentReferences(RootComponent: TComponent;
                         OpenFlags: TOpenFlags): TModalResult; virtual; abstract;
 
@@ -352,50 +348,6 @@ begin
   UpdateCaption;
 end;
 
-function TMainIDEInterface.ExtendProjectUnitSearchPath(AProject: TProject;
-  NewUnitPaths: string): boolean;
-var
-  CurUnitPaths: String;
-  r: TModalResult;
-begin
-  CurUnitPaths:=AProject.CompilerOptions.ParsedOpts.GetParsedValue(pcosUnitPath);
-  NewUnitPaths:=RemoveSearchPaths(NewUnitPaths,CurUnitPaths);
-  if NewUnitPaths<>'' then begin
-    NewUnitPaths:=CreateRelativeSearchPath(NewUnitPaths,AProject.ProjectDirectory);
-    r:=IDEMessageDialog(lisExtendUnitPath,
-      Format(lisExtendUnitSearchPathOfProjectWith, [#13, NewUnitPaths]),
-      mtConfirmation, [mbYes, mbNo, mbCancel]);
-    case r of
-    mrYes: AProject.CompilerOptions.MergeToUnitPaths(NewUnitPaths);
-    mrNo: ;
-    else exit(false);
-    end;
-  end;
-  Result:=true;
-end;
-
-function TMainIDEInterface.ExtendProjectIncSearchPath(AProject: TProject;
-  NewIncPaths: string): boolean;
-var
-  CurIncPaths: String;
-  r: TModalResult;
-begin
-  CurIncPaths:=AProject.CompilerOptions.ParsedOpts.GetParsedValue(pcosIncludePath);
-  NewIncPaths:=RemoveSearchPaths(NewIncPaths,CurIncPaths);
-  if NewIncPaths<>'' then begin
-    NewIncPaths:=CreateRelativeSearchPath(NewIncPaths,AProject.ProjectDirectory);
-    r:=IDEMessageDialog(lisExtendIncludePath,
-      Format(lisExtendIncludeFilesSearchPathOfProjectWith, [#13, NewIncPaths]),
-      mtConfirmation, [mbYes, mbNo, mbCancel]);
-    case r of
-    mrYes: AProject.CompilerOptions.MergeToIncludePaths(NewIncPaths);
-    mrNo: ;
-    else exit(false);
-    end;
-  end;
-  Result:=true;
-end;
-
 function TMainIDEInterface.DoJumpToSourcePosition(const Filename: string; NewX, NewY,
   NewTopLine: integer; AddJumpPoint: boolean; MarkLine: Boolean): TModalResult;
 var
diff --git a/ide/project.pp b/ide/project.pp
index 42a3426028..c0fc413c34 100644
--- a/ide/project.pp
+++ b/ide/project.pp
@@ -1014,6 +1014,8 @@ type
     function GetStateFilename: string;
     function GetCompileSourceFilename: string;
     procedure AutoAddOutputDirToIncPath;
+    function ExtendUnitSearchPath(NewUnitPaths: string): boolean;
+    function ExtendIncSearchPath(NewIncPaths: string): boolean;
 
     // compile state file
     function LoadStateFile(IgnoreErrors: boolean): TModalResult;
@@ -4883,6 +4885,48 @@ begin
   end;
 end;
 
+function TProject.ExtendUnitSearchPath(NewUnitPaths: string): boolean;
+var
+  CurUnitPaths: String;
+  r: TModalResult;
+begin
+  CurUnitPaths:=CompilerOptions.ParsedOpts.GetParsedValue(pcosUnitPath);
+  NewUnitPaths:=RemoveSearchPaths(NewUnitPaths,CurUnitPaths);
+  if NewUnitPaths<>'' then begin
+    NewUnitPaths:=CreateRelativeSearchPath(NewUnitPaths,ProjectDirectory);
+    r:=IDEMessageDialog(lisExtendUnitPath,
+      Format(lisExtendUnitSearchPathOfProjectWith, [#13, NewUnitPaths]),
+      mtConfirmation, [mbYes, mbNo, mbCancel]);
+    case r of
+    mrYes: CompilerOptions.MergeToUnitPaths(NewUnitPaths);
+    mrNo: ;
+    else exit(false);
+    end;
+  end;
+  Result:=true;
+end;
+
+function TProject.ExtendIncSearchPath(NewIncPaths: string): boolean;
+var
+  CurIncPaths: String;
+  r: TModalResult;
+begin
+  CurIncPaths:=CompilerOptions.ParsedOpts.GetParsedValue(pcosIncludePath);
+  NewIncPaths:=RemoveSearchPaths(NewIncPaths,CurIncPaths);
+  if NewIncPaths<>'' then begin
+    NewIncPaths:=CreateRelativeSearchPath(NewIncPaths,ProjectDirectory);
+    r:=IDEMessageDialog(lisExtendIncludePath,
+      Format(lisExtendIncludeFilesSearchPathOfProjectWith, [#13, NewIncPaths]),
+      mtConfirmation, [mbYes, mbNo, mbCancel]);
+    case r of
+    mrYes: CompilerOptions.MergeToIncludePaths(NewIncPaths);
+    mrNo: ;
+    else exit(false);
+    end;
+  end;
+  Result:=true;
+end;
+
 function TProject.LoadStateFile(IgnoreErrors: boolean): TModalResult;
 var
   XMLConfig: TXMLConfig;
diff --git a/ide/projectinspector.pas b/ide/projectinspector.pas
index f16825ca0f..0f33a2415a 100644
--- a/ide/projectinspector.pas
+++ b/ide/projectinspector.pas
@@ -1252,12 +1252,12 @@ end;
 
 function TProjectInspectorForm.ExtendIncSearchPath(NewIncPaths: string): boolean;
 begin
-  Result:=MainIDEInterface.ExtendProjectIncSearchPath(LazProject,NewIncPaths);
+  Result:=LazProject.ExtendIncSearchPath(NewIncPaths);
 end;
 
 function TProjectInspectorForm.ExtendUnitSearchPath(NewUnitPaths: string): boolean;
 begin
-  Result:=MainIDEInterface.ExtendProjectUnitSearchPath(LazProject,NewUnitPaths);
+  Result:=LazProject.ExtendUnitSearchPath(NewUnitPaths);
 end;
 
 function TProjectInspectorForm.FilesBaseDirectory: string;