A simplified and speeded up version of mshang47's project. Just start with the green flag (turbo mode recommended - shift and click green flag to enable)
I removed mode 2 so it just looks for primes from the beginning. 2 is loaded manually so we only need to check odd numbers and don't need to test divisibility by 2. We only need to check factors up to the square root of the number being tested which also saves time. Finally I added a button to hide/show the list of primes and time - not showing the list should make it faster. (And later added an indicator of the last prime found.) These changes make it much faster than the original.
