Bug 370436 - "Context menu from keyboard for spell checker selects the wrong line" [r=roc]

layout/base/nsPresShell.cpp

@@ -6776,6 +6776,10 @@ PresShell::PrepareToUseCaretPosition(nsIWidget* aEventWidget, nsIntPoint& aTarge
   aTargetPt.x = presContext->AppUnitsToDevPixels(viewDelta.x + caretCoords.x + caretCoords.width);
   aTargetPt.y = presContext->AppUnitsToDevPixels(viewDelta.y + caretCoords.y + caretCoords.height);
 
+  // make sure rounding doesn't return a pixel which is outside the caret
+  // (e.g. one line lower)
+  aTargetPt.y -= 1;
+
   return PR_TRUE;
 }