diff --git a/ide/main.pp b/ide/main.pp
index 6b15e08d30..e77c756c55 100644
--- a/ide/main.pp
+++ b/ide/main.pp
@@ -6110,7 +6110,7 @@ begin
   DebugLn(['TMainIDE.CloseUnitComponent ',AnUnitInfo.Filename,' ',dbgsName(LookupRoot)]);
   {$ENDIF}
 
-  Project1.LockUnitComponentDependencies;
+  Project1.LockUnitComponentDependencies; // avoid circles
   try
     // save
     if (cfSaveFirst in Flags) and (AnUnitInfo.EditorIndex>=0)
@@ -6269,6 +6269,7 @@ begin
   Project1.UpdateUnitComponentDependencies;
   if Project1.UnitComponentIsUsed(AnUnitInfo,CheckHasDesigner) then
     exit(true);
+  //DebugLn(['TMainIDE.UnitComponentIsUsed ',AnUnitInfo.Filename,' ',dbgs(AnUnitInfo.Flags)]);
 end;
 
 function TMainIDE.GetAncestorUnit(AnUnitInfo: TUnitInfo): TUnitInfo;
diff --git a/ide/project.pp b/ide/project.pp
index 560e9fa13f..7f4848115d 100644
--- a/ide/project.pp
+++ b/ide/project.pp
@@ -1144,7 +1144,7 @@ procedure TUnitInfo.WriteDebugReportUnitComponentDependencies(Prefix: string);
 var
   Dependency: TUnitComponentDependency;
 begin
-  DebugLn([Prefix+'TUnitInfo.WriteDebugReportUnitComponentDependencies ',Filename]);
+  DebugLn([Prefix+'TUnitInfo.WriteDebugReportUnitComponentDependencies ',Filename,' ',dbgs(Flags)]);
   Dependency:=FirstRequiredComponent;
   if Dependency<>nil then begin
     DebugLn([Prefix+'  Requires:  >>> ']);
@@ -3734,7 +3734,7 @@ procedure TProject.UpdateUnitComponentDependencies;
     until TypeInfo=nil;
   end;
   
-  procedure DFSUsedByDesigner(AnUnitInfo, IgnoreUnitInfo: TUnitInfo);
+  procedure DFSRequiredDesigner(AnUnitInfo, IgnoreUnitInfo: TUnitInfo);
   var
     Dependency: TUnitComponentDependency;
     UsingUnitInfo: TUnitInfo;
@@ -3743,19 +3743,19 @@ procedure TProject.UpdateUnitComponentDependencies;
     or (uifMarked in AnUnitInfo.FFlags) then
       exit;
     Include(AnUnitInfo.FFlags,uifMarked);
-    Dependency:=AnUnitInfo.FirstUsedByComponent;
+    Dependency:=AnUnitInfo.FirstRequiredComponent;
     while Dependency<>nil do begin
-      UsingUnitInfo:=Dependency.UsedByUnit;
+      UsingUnitInfo:=Dependency.RequiresUnit;
       if (UsingUnitInfo<>IgnoreUnitInfo)
       and (not (uifComponentIndirectlyUsedByDesigner in UsingUnitInfo.FFlags))
       then begin
         {$IFDEF VerboseIDEMultiForm}
-        DebugLn(['TProject.UpdateUnitComponentDependencies.DFSUsedByDesigner designer of ',UsingUnitInfo.Filename,' uses ',AnUnitInfo.Filename]);
+        DebugLn(['TProject.UpdateUnitComponentDependencies.DFSRequiredDesigner designer of ',AnUnitInfo.Filename,' uses ',UsingUnitInfo.Filename]);
         {$ENDIF}
         Include(UsingUnitInfo.FFlags,uifComponentIndirectlyUsedByDesigner);
-        DFSUsedByDesigner(UsingUnitInfo,IgnoreUnitInfo);
+        DFSRequiredDesigner(UsingUnitInfo,IgnoreUnitInfo);
       end;
-      Dependency:=Dependency.NextUsedByDependency;
+      Dependency:=Dependency.NextRequiresDependency;
     end;
   end;
 
@@ -3808,7 +3808,7 @@ begin
       begin
         // mark all that use indirectly this designer
         Exclude(AnUnitInfo.FFlags,uifMarked);
-        DFSUsedByDesigner(AnUnitInfo,AnUnitInfo);
+        DFSRequiredDesigner(AnUnitInfo,AnUnitInfo);
       end;
       AnUnitInfo:=AnUnitInfo.NextUnitWithComponent;
     end;