Better default tooltip & ability to customize the tooltip in charts

[arikfr]

Better default tooltip

• It will be better to switch to something more similar to the tooltip format we used with the HighCharts charts, where it was clearer what is the X axis and was is the Y.
• While at it, we should show dates as date only and time as date/time ("1/1/2016 vs. 1/1/2016 00:00").

Ability to customize the tooltip

The user should be able to provide his own tooltip value (based on one of the columns).

[alaincaltieri]

Hi Arikfr,

Linked to this issue, I think it may be really useful to have in the tooltips also the grand totals when there's a stacked data visualisation. Let me show an example:

As you see the tooltip shows the amount of each group, but it doesn't show the total summed amount, which may really come in handy sometimes.

[arikfr]

@alaincaltieri good point. I'll remember that once I get to this ticket. Thanks!

[arikfr]

Implemented in #2536.