Following up on this comment, I noticed that calling Screen.Clear() prior to Screen.Show() (and after drawing other elements) leads to full-screen flickering on Windows. It's as if the call to Clear() immediately clears the screen instead of deferring it to Show(). The comment above illustrates this with a video. Here is the relevant code in tview. If I remove the call to Clear(), there is no flickering anymore (but this has other unintended side effects, so I would like to keep Clear() there).

Is this the intended behaviour? If so, what's the best way to clear the screen buffer at the beginning of a drawing cycle?