Ticking 'Calculate as a portfolio' in the settings will display the 'Weight' column and 'Rebalance' / 'Save' buttons.
Individual product weights can be modified or the product weights can be rebalanced to 100% automatically using the 'Rebalance' button.
Products not selected will be excluded when rebalancing.
The performance of individual products within a portfolio can be analysed by simply un-ticking 'Calculate as a portfolio' and re-generating the charts. The 'Weight' column will be become hidden however the assigned product weights will be retained.