diff --git a/win32ss/user/ntuser/desktop.c b/win32ss/user/ntuser/desktop.c
index 6ecf94b30e8..4d7f76bbdb8 100644
--- a/win32ss/user/ntuser/desktop.c
+++ b/win32ss/user/ntuser/desktop.c
@@ -932,6 +932,7 @@ UserGetDesktopDC(ULONG DcType, BOOL EmptyDC, BOOL ValidatehWnd)
     PWND DesktopObject = 0;
     HDC DesktopHDC = 0;
 
+    /* This can be called from GDI/DX, so acquire the USER lock */
     UserEnterExclusive();
 
     if (DcType == DC_TYPE_DIRECT)