ScrollFlags::NoErase is never set

Change-Id: I0cd0140b26100c6cd6d91ad060526310ef2ba7f6

include/vcl/window.hxx

@@ -254,13 +254,12 @@ enum class ScrollFlags
     Clip                     = 0x0001,
     Children                 = 0x0002,
     NoChildren               = 0x0004,
-    NoErase                  = 0x0008,
-    UseClipRegion            = 0x0010,
-    Update                   = 0x0020,
+    UseClipRegion            = 0x0008,
+    Update                   = 0x0010,
 };
 namespace o3tl
 {
-    template<> struct typed_flags<ScrollFlags> : is_typed_flags<ScrollFlags, 0x003f> {};
+    template<> struct typed_flags<ScrollFlags> : is_typed_flags<ScrollFlags, 0x001f> {};
 }
 
 // Flags for ParentClipMode

vcl/source/window/paint.cxx

@@ -1542,7 +1542,6 @@ void Window::ImplScroll( const Rectangle& rRect,
 
     vcl::Region  aInvalidateRegion;
     bool    bScrollChildren(nFlags & ScrollFlags::Children);
-    bool    bErase(!(nFlags & ScrollFlags::NoErase));
 
     if ( !mpWindowImpl->mpFirstChild )
         bScrollChildren = false;
@@ -1572,7 +1571,6 @@ void Window::ImplScroll( const Rectangle& rRect,
     if (!aInvalidateRegion.IsEmpty())
     {
         aInvalidateRegion.Move(bReMirror ? -nHorzScroll : nHorzScroll, nVertScroll);
-        bErase = true;
     }
 
     Rectangle aDestRect(aRectMirror);
@@ -1661,8 +1659,6 @@ void Window::ImplScroll( const Rectangle& rRect,
         mpWindowImpl->mnPaintFlags |= IMPL_PAINT_CHECKRTL;
 
         InvalidateFlags nPaintFlags = InvalidateFlags::Children;
-        if ( !bErase )
-            nPaintFlags |= InvalidateFlags::NoErase;
         if ( !bScrollChildren )
         {
             if ( nOrgFlags & ScrollFlags::NoChildren )