Custom Expression Manager Merged

A mechanism is needed to manage and edit all custom expressions at a document level and then by reference not have to repeat them by chart or property control.  Currently we employ document properties to manage large or complex expressions, and any that that repeat in multiple visualizations, creating a single point of maintenance: the document property.  All visualization expressions, property controls such as list box of expressions, etc. refer to document properties and do not use hard coded expressions.  This technique dramatically simplifies maintenance and speeds up the development of dashboards   

An easy work around would have the expression editor itself callable from the Document Properties editing dialogue rather than the simple text box available now, but a formal system of managing, referencing, and reusing custom expressions would move Spotfire forward as an analytic application development platform.