Hi Einar Dørheim,
I did find that this could be done, unfortunately, most data is not setup this way. Forcing data into a restricted schema in order to use these widgets isn't really a viable solution.
Imagine if you have dozens of well sites, and you need to measure their depths each month, and you can only do a few each day. To keep data entry simple for the end user (which is incredibly important, I can't stress this enough), the data structure goes: Well Site, Date (auto), Well Depth. Your series are based on the well site, the Y axis is the depth, and the X axis is the date. If you want to use the multi-line feature, you would need to structure your data something like this: Month, Well 1 Depth, Well 2 Depth, Well 3 Depth... Well N Depth. And even here, you will loose the exact date that the depth was captured unless you also put a date field next to each one. This also forces users to edit the same record multiple times, which will likely result in a lot of user error.
You could use something like FME to automatically restructure the data in this format, but at that point, I might as well be making a custom app or exporting the data into a report that's emailed to the operations group.
