ScreenFlow User Guide | Text Capabilities — Changes over Time
| Video Properties All of the Video Properties applied to Text Box clips will be respected as part of a Video Action. This allows Text Boxes to move around the canvas in 3D just as any other Media in the Timeline. Since they also respect Opacity, it’s easy to build simple Fade-In Transitions using Text Boxes. Text Properties None of the Text Properties are currently changeable over time for a Text Box clip. This means that when you change properties of a piece of text, those properties are changed for that Text Box clip for the whole length of the Timeline.