This has bugged me as well; the new error bar interface is incomplete and
confusing. I don't know why they took it out of the Format Series dialog. If
you go to Chart Tools > Layout tab > Analysis group > Error Bars dropdown >
More Error Bars Options, it pops up a dialog that says "Format Error Bars",
with only the Vertical Error Bars listed. When you dismiss this dialog, both
sets of error bars appear, and you can click on either to refine their
formats or data.
- Jon
