The title describes the problem.
I can use fullScreen() to cover the screen with a window on any monitor. But it doesn’t have a title bar.
The following code creates a window with a title bar that covers the screen. But only for the default monitor. (Also, the positioning is wrong, since a bug persists from years ago.)
void settings() {
size(displayWidth, displayHeight);
}
void setup() {
surface.setTitle("my application");
surface.setLocation(0, 0);
}
void draw() {
background(0);
fill(200);
circle(mouseX, mouseY, width/4.);
}