The VtFrameStyle constants provide options for displaying backdrop frames.
| Constant | Description |
| VtFrameStyleNull | No frame. |
| VtFrameStyleSingleLine | A single line encloses the backdrop. |
| VtFrameStyleDoubleLine | Two equal width lines enclose the backdrop. |
| VtFrameStyleThickInner | A thick inner line and a thin outer line enclose the backdrop. |
| VtFrameStyleThickOuter | A thin inner line and a thick outer line enclose the backdrop. |