Create trend line without selecting data series

When I try to create a trend line without first selecting a data series, the Trend Line option is grayed out. Does Calc require that we select one or more data series before this option is available?
If it does not, how can I make it available?

It is a matter of definition. A trend line requires some data for which to establish a trend. It is the trend of the data that is being graphed; therefore, you must select a data series for the line. I know of no other way.

If you wish to show some arbitrary line on your chart, say for a threshold or a limit, you could create a data series with appropriate values and select it as the required data series. I have done this, using values for only the end-points, for some of my own charts.

Thank you. I should have been clearer. I asked because the user guide says that if no data series is selected, then a trend line will be created for all of the data.

So, I am checking to see if the user guide is correct. It appears that it is not.

Interesting. I was not aware of the statement in the user guide. Playing around a bit (v5.4), I could not find a way to select more than one series of data in order to create a trend line. It seems that the ability to create a trend line for all of the data has been lost in recent versions, if it ever really existed. It should be reported as a bug.

You didn’t say which version you are using. Perhaps someone with more skill than mine can suggest a solution to you. .

Yes, both the Calc user guide and the online help say this. If it is not true, I will make sure that the information in both places is corrected.

Thank you for looking into this.