We currently have at least 3 different drop down menus in the portal (see below), none of which are great. The new one that has been designed is definitely an improvement and needs to get implemented. That said I wanted to note a few additional requirements:
For multi-select versions have an ever present 'All' choice which will enable users to have new portfolios added dynamically
For multi-select versions support the Shift key to enable multi-select of ranges
Allow wildcards so users can define their portfolio sets dynamically