--- Comment #16 from [hidden email] ---
Of course, traditional Y-only error bars are still needed in other contexts.
The combined settings dialog proposed by Winfried and me could handle these
cases. In the "general" tab, the user will not choose the "rectangle" option,
but "bar / whiskers" (it could be the default) and of course no need to visit
the X error tab in this case (they will have a value of 0, so no X error bars).
The chart menu should be modified also with only one option to insert error
bars (not one for X and another for Y) that would call the combined dialog.