diff --git a/reactos/base/applications/calc/winmain.c b/reactos/base/applications/calc/winmain.c
index 8a5af2f127f..01b9a992c4b 100644
--- a/reactos/base/applications/calc/winmain.c
+++ b/reactos/base/applications/calc/winmain.c
@@ -212,8 +212,8 @@ static const function_table_t function_table[] = {
     { IDC_BUTTON_DMS,  MODIFIER_INV,              1, rpn_dec2dms, rpn_dms2dec, NULL,     NULL      },
     { IDC_BUTTON_FE,   0,                         1, run_fe,      NULL,        NULL,     NULL      },
     { IDC_BUTTON_DAT,  0,                         1, run_dat_sta, NULL,        NULL,     NULL,     },
-    { IDC_BUTTON_MP,   MODIFIER_INV,              1, run_mp,      run_mm,      NULL,     NULL,     },
-    { IDC_BUTTON_MS,   MODIFIER_INV,              1, run_ms,      run_mw,      NULL,     NULL,     },
+    { IDC_BUTTON_MP,   MODIFIER_INV|NO_CHAIN,     1, run_mp,      run_mm,      NULL,     NULL,     },
+    { IDC_BUTTON_MS,   MODIFIER_INV|NO_CHAIN,     1, run_ms,      run_mw,      NULL,     NULL,     },
     { IDC_BUTTON_CANC, NO_CHAIN,                  0, run_canc,    NULL,        NULL,     NULL,     },
     { IDC_BUTTON_RIGHTPAR, NO_CHAIN,              1, run_rpar,    NULL,        NULL,     NULL,     },
     { IDC_BUTTON_LEFTPAR,  NO_CHAIN,              0, run_lpar,    NULL,        NULL,     NULL,     },