From Xojo Documentation
Oval is used to display ovals and circles on the layout. The user does not typically interact with this control.
Below are commonly used properties. Refer to MobileOval in the Language Reference for the complete list.
BorderColor - The color that the border is drawn.
BorderThickness - The width (or thickness) of the border.
FillColor - The color for the filled area of the oval.
Set the FillColor: