diff --git a/reactos/subsystems/win32/win32k/objects/bitmaps.c b/reactos/subsystems/win32/win32k/objects/bitmaps.c
index 43fb0e326a6..ff268aee825 100644
--- a/reactos/subsystems/win32/win32k/objects/bitmaps.c
+++ b/reactos/subsystems/win32/win32k/objects/bitmaps.c
@@ -785,7 +785,7 @@ BITMAP_CopyBitmap(HBITMAP hBitmap)
     /* Allocate a new bitmap with the same dimensions as the source bmp */
     hbmNew = GreCreateBitmapEx(psurfSrc->SurfObj.sizlBitmap.cx,
                                psurfSrc->SurfObj.sizlBitmap.cy,
-                               psurfSrc->SurfObj.lDelta,
+                               abs(psurfSrc->SurfObj.lDelta),
                                psurfSrc->SurfObj.iBitmapFormat,
                                psurfSrc->SurfObj.fjBitmap,
                                psurfSrc->SurfObj.cjBits,