[R-SIG-Finance] addTA on an existing subchart

[Robert Nicholson]

Is this supported yet?

docs say

The on is used to identify which subchart to add the graphic to. By default, on=NA will draw the series in a new subchart below the last indicator. Setting this to either a positive or negative value will allow for the series to be super-imposed on, or under, the (sub)chart specified, respectively. A value of 1 refers to the main chart, and at present is the only location supported.