The style system in the versions prior to Spread for WinForms 12 will continue to behave as before. However, if you're creating a new project in the latest version i.e. Spread for WinForms 12, some behaviors may seem different.

Spread for WinForms 12 supports the new style system - Flat Mode Style system that works similar to Excel. Users can access full functions of the new style system with new API set only.

If users need to set style via SheetView and or cell APIs, and if the LegacyBehaviors property doesn't contains the LegacyBehaviors.Style, the corresponding new APIs will be invoked. Else, the old style system will work as before.            

By default, Spread for WinForms will use the old style system only when the control instance is created using the default constructor (new FpSpread() with no arguments), and new instances of the control created in design time will be created using a new constructor specifying LegacyBehaviors.None and use the new style system.

In order to use the new style system, users can use the following line of code:

FpSpread.LegacyBehaviors &= ~LegacyBehaviors.Style;