How to protect 2. axis in an Excel Chart to stay if data changes
 

A Pivot table is created on Tab1 in an Excel workbook. On Tab2 there is a
Line Chart created with data from Tab 1 using 2 axis.
If data in Tab1 change the 2nd axis on Tab 2 disappears, jumps ober and
overrules axis 1.

How can I protect chart area with 2 axis being able to change referring data
in the pivot table.