The Master Item List is color-coded so you can identify Items sized by Styles or Styles with Sizes (blue), Items that are part of a Mixture (ping, and Items that are the start of a Chain (link icon).
Mixtures
Items that are "Sized" as a Mixture are color coded PINK in the Item list. Mixtures are Items that are composed of some amount of some Items to create a specific "coverage". See Related Articles for more information about Mixtures.
Styles or Styles with Sizes
Items Sized by Styles or Styles with Sizes are color coded BLUE in the Item list. Sizing, including Styles and Styles with Sizes, is detailed in Related Articles.
Items That Start a Chain
Items that display the chain link symbol 
in the far-left column are the start of a Chain.
Chains are used to insert related Items into a Condition Detail automatically.
Double-click X58 to open its Item Detail.
Notice, there are two Chained Items: TF4 (which is also a Mixture!) and DS. When you add X58 to a Condition Detail, these two Chained Items are included automatically.
See Related Articles for details on using Chains.
Items List: Column Selector