I have this sidespace in the grid dedicated to show the expansion buttons:
But I can't find any style setting(even in override) that let me change that backcolor.
If there's any, where I can find this style setting?
Thank you for contacting Infragistics. Based on your image, it appears you want to style the GroupByRowConnector.
If your grid is not grouped, please provide a larger image and some setup code demonstrating your view.
Yes, this is the component of interest but I discovered that it's overriden by DisplayLayout.Appearance.BackColor because otherwise it doesn't update the BackColor setup at GroupByRowConnector, thanks anyway for the support.
If you could send us a small isolated sample I would take a look at it. Thanks.