diff --git a/reactos/subsystems/win32/win32k/ntuser/simplecall.c b/reactos/subsystems/win32/win32k/ntuser/simplecall.c
index 87d8c07dc3a..d4a1a14f403 100644
--- a/reactos/subsystems/win32/win32k/ntuser/simplecall.c
+++ b/reactos/subsystems/win32/win32k/ntuser/simplecall.c
@@ -187,7 +187,7 @@ NtUserCallOneParam(
              RtlZeroMemory(psmwp->acvr, count * sizeof(CVR));
              psmwp->bHandle = TRUE;
              psmwp->ccvr = 0;          // actualCount
-             psmwp->ccvrAlloc = Param; // suggestedCount             
+             psmwp->ccvrAlloc = count; // suggestedCount             
              RETURN((DWORD_PTR)hDwp);
          }