Colour Expression - Stacked Area Chart

[#1]

I am trying to create a stacked area chart (from the line chart) in QlikSense.

The chart itself is fine, and when using a default colour scheme the areas are filled as you would expect. However in order to ensure consistency through the app, I am using the expression below to replicate the same colour scheme as in the other charts:

Pick(Match("Region", '1', '2', '3', '4', '5'), '#00746D', '#FFCE51', '#820053', '#00539B', '#002B5C')

However this is resulting in just the lines being coloured, leaving the stacked areas greyed out.

Is there any way of rectifying this?