color
Colors a tooltip's border.
This option supports the following colors:
- Hexadecimal colors
- RGB colors
- RGBA colors
- Predefined/cross-browser color names
- Predefined SVG colors
dashStyle
Specifies the dash style of a tooltip's border.
The following dash styles are available:
- solid 
 The border is a solid, continuous line.
- longDash 
 The border is displayed using long dashes.
- dash 
 The border is displayed using dashes.
- dot 
 The border is displayed using dots.
- Any combination of 'longDash', 'dash' and 'dot' 
 The border is displayed by repeating the specified combination. For instance, 'dashdotdash'.
Use the DashStyle enum to specify this option when the widget is used as an ASP.NET MVC 5 Control or a DevExtreme-Based ASP.NET Core Control. This enum accepts the following values: Solid, LongDash, Dash, and Dot.
opacity
Specifies the transparency of a tooltip's border.
This option accepts a value from 0 to 1, where 0 makes the border completely transparent, and 1 makes it opaque.
If you have technical questions, please create a support ticket in the DevExpress Support Center.