diff --git a/Designing/WinLib/WinCreate.lua b/Designing/WinLib/WinCreate.lua
index b3c66e8..5c4d703 100644
--- a/Designing/WinLib/WinCreate.lua
+++ b/Designing/WinLib/WinCreate.lua
@@ -255,17 +255,10 @@ local function IdentifySashShape( nAreaId, nOutlineLayerId)
                EgtSetInfo( nAreaId, WIN_SASH_SHAPE, WIN_SASH_SHAPES.SEGMENTAL_ARC)
             else
                -- verifico se metà di arco a tutto sesto o ribassato
-               if abs( dAngCenter - 90) < GEO.EPS_SMALL then
+               if AreSameVectorApprox( EgtEV( vOutlines[2]), EgtSV( vOutlines[3])) or AreSameVectorApprox( EgtEV( vOutlines[3]), EgtSV( vOutlines[4])) then
                   EgtSetInfo( nAreaId, WIN_SASH_SHAPE, WIN_SASH_SHAPES.SEMI_ROUND_ARC)
                else
-                  local ptS = EgtSP( vOutlines[3])
-                  local ptE = EgtEP( vOutlines[3])
-                  local ptC = EgtCP( vOutlines[3])
-                  if abs( ptS:getX() - ptC:getX()) < GEO.EPS_SMALL or abs( ptE:getX() - ptC:getX()) < GEO.EPS_SMALL then
-                     EgtSetInfo( nAreaId, WIN_SASH_SHAPE, WIN_SASH_SHAPES.SEMI_SEGMENTAL_ARC)
-                  else
-                     EgtSetInfo( nAreaId, WIN_SASH_SHAPE, WIN_SASH_SHAPES.GENERIC)
-                  end
+                  EgtSetInfo( nAreaId, WIN_SASH_SHAPE, WIN_SASH_SHAPES.SEMI_SEGMENTAL_ARC)
                end
             end
          end