Pivot Chart with Slicers, Trendline Problem.

[Masterz13]

Hello Excel people!

I've been working on a report, showing the total hours provided by each supplier, broken down by the Zone they are based.

I've attached an image to show you, this is a Pivot Chart, controlled by slicers including a Linear Trend line Forecast. currently showing all suppliers.

I want the user to be able to select certain suppliers, so they can see whish zones they provide hours for, and if they are increasing/decreasing over time, with a the trend line forecast as well.

Now, if the Provider appears in all 4 zones, the trend lines remain. However for example if a certain provider only appears in West and Central, the graph changes and the trend lines disappear, they then do not Re-appear when all providers are reselected.

I've blocked out the supplier names on the image.

Does anybody have any idea how I can have the trend lines remain regardless of what is selected on my slicers?

Ive never used VBA so if there is a Non-Vba way to do this, that would be best. If not, please can you give me instructions how to use VBA!

Thanks

https://drive.google.com/file/d/0BzrEJfijuWqrWnh5bkhpQ0pqbjQ/view?usp=sharing