GSGokul Sainarayanan Syncfusion Team February 5, 2020 08:35 AM
Thank you for contacting Syncfusion support.
We have checked your reported query regarding the Office2019Colorful theme. The Office2019 and HighContrast themes are implemented in a separate assembly which will be loaded only in the runtime from the static Main constructor, hence these themes will not be applied to the controls during the design time. This kind of implementation is done as it helps us to load these themes and modify and generate custom theme assemblies using WinForms ThemeStudio. The older themes till Office2016 do not have ThemeStudio support as they are implemented in their corresponding control’s assembly instead of the separate assembly.