By default TabControl and its panels use the colors that are pre-determined by the style that is set using TabControl.Style property.

To customize TabControlPanel colors which hosts the controls you add to the tab follow these steps:

1. Select TabControlPanel in VS.NET designer.
2. Set UseCustomStyle = true
3. Set Style object properties to change the visual appearance of the tab. For example to change background color set Style.BackColor1.Color and Style.BackColor2.Color properties.

To customize actual tab colors you can select each tab and use properties on a tab to customize its colors (BackColor, BackColor2 etc.)

You can also customize all colors used by the current tab style by changing properties on TabControl.ColorScheme object.