PhiPhenomenon wrote:

The paint bucket works by filling in the exact same colors that are next to the current pixel. The reason why it's leaving dots is because those dots don't exactly match the color of the other pixels. You'll have to use the brush tool to fill those in yourself.

Color tolerance in Scratch would be useful, but unfortunately, the dev team hasn't added that. =[

Yes, but even if I make a single color square or circle, it still happens.