diff --git a/rtdata/languages/default b/rtdata/languages/default
index bf400c39f..352c4f92e 100644
--- a/rtdata/languages/default
+++ b/rtdata/languages/default
@@ -819,6 +819,7 @@ MAIN_TAB_WAVELET_TOOLTIP;Shortcut: <b>Alt-w</b>
 MAIN_TOOLTIP_BACKCOLOR0;Background color of the preview: <b>Theme-based</b>\nShortcut: <b>9</b>
 MAIN_TOOLTIP_BACKCOLOR1;Background color of the preview: <b>Black</b>\nShortcut: <b>9</b>
 MAIN_TOOLTIP_BACKCOLOR2;Background color of the preview: <b>White</b>\nShortcut: <b>9</b>
+MAIN_TOOLTIP_BACKCOLOR3;Background color of the preview: <b>Middle grey</b>\nShortcut: <b>9</b>
 MAIN_TOOLTIP_BEFOREAFTERLOCK;<b>Lock</b> / <b>Unlock</b> the <b>Before</b> view\n\n<b>Lock</b>: keep the <b>Before</b> view unchanged.\nUseful to evaluate the cumulative effect of multiple tools.\nAdditionally, comparisons can be made to any state in the History.\n\n<b>Unlock</b>: the <b>Before</b> view will follow the <b>After</b> view one step behind, showing the image before the effect of the currently used tool.
 MAIN_TOOLTIP_HIDEHP;Show/Hide the left panel (including the history).\nShortcut: <b>l</b>
 MAIN_TOOLTIP_INDCLIPPEDH;Clipped highlight indication.\nShortcut: <b>&lt;</b>