Dimension & Expression Change Based on Selection?

[#1]

If you look at the "scatter plot comparison" tab on the follow demo:

http://gcr.weforum.org/gcr09/?document=World%20Economics%20Forum.qvw&host=Demo10&anonymous=true

you can select a dimension and an expression and it changes the chart. Sadly I can't just right click properties, but I'm interested in how they did this. Anyone have any ideas?

Thanks in advance.

[#2]

You need to create fields to store your list of dimensions and expressions. You can use an Inline load or pull from a database.

LOAD * INLINE [
 Dimensions
 Customer
 Region
 Store
];

Then use GetFieldSelections(Dimensions) to tell you what the user has selected. For dimension, create a Calculated Dimension:

If(GetFieldSelections(Dimensions) = 'Customer', Customer, Region)

Something like that.

There are other considerations, like requiring a selection and handling multiple selections, but that should give you a start.