Generally most Column styles set the background color for the active cell using the Appearance.BackColor or ActiveAppearance.BackColor on the activate event of the cell. This works for most of the column styles. Some column styles such as DropDownList and EditButton do not set the background color. I have attempted to work around the issue by using the EditorResolved .SelectedTextBackColor but that only goes so far. Anyone have any ideas on this? Thanks.
When the column's Style is set to EditButton, you can use the UltraGridColumn.CellButtonAppearance to style the button. Note that if OS theming is enabled, you would have to set the ThemedElementAlpha property of the CellButtonAppearance in order to see the color. The Active state appearances are not applied to the cell's edit button, but is rather applied to the edit area of the cell, and this is by design. You can probably override this using AppStyling, i.e., by using the appearance for the CellButton role for the Active state.
When the column's Style is set to DropDownList, the ActiveAppearance is applied to the cell's edit area as with all the other styles, so if you're not seeing that, I'm not able to reproduce the issue with a simple test. If you want to attach a sample that demonstrates the issue, we'll take a look and let you know what's going on there.