Input attribute of selection dropdown type.
The State Editor will display this input attribute using a selection dropdown component with preset list. User can select a value from the dropdown list but not entering a new one.
By default, the SelectionBoxAttribute has a InputAttribute.InputType#ATTRIBUTE type, so the input attribute checkbox will be unchecked, and it means the value is static and will be used as is. The choice made by the user on the State Editor will be treated as a static value, and used as is. The dropdown is populated with a "Key-Value" list, and the selected value is the "Key". The "Value" is the displayed text shown on the UI.
This SelectionBoxAttribute can also be set to InputAttribute.InputType#SESSION type, to retrieve the value from the session variable. The name of the session variable will be the ID of this selectionbox attribute, and it cannot be changed. On the state editor, the ID will be shown on mouse-hover over the input attribute description. When set to the InputAttribute.InputType#SESSION type, the selection should be left null.