I'm working on an analog clock, just because...
Ben, thanks for creating the library! It will make my life a lot better anyway.
I looked at the new basic example project and I see a comment about a delay not being in the draw commands because it's not always needed. I realize now, what I really needed was a delay after the clearWindow command, setBrighness must have added enough delay.
Replace loop in TinyScreen_Demo with this to see what I was talking about, assuming it happens for you. I guess now, you just need to follow clearWindow with a draw command to repro what I was seeing.
void loop() {
display.setCursor(15,20);
display.fontColor(BLACK,WHITE);
display.clearWindow(0,0,96,64);
// display.setBrightness(15);
display.drawRect(20,20,25,30,1,WHITE);
display.print("BRIGHT!");
delay(5000);
}