Right now on the tokens layer specifically it changes to your player color every time you re-select the tool. So you can choose a color to draw something, draw as many strokes as you want, then if you come back to draw something else later it switches back to the default.
My thinking on this was that you would mostly draw notes/battle pan type sketches on the tokens layer, and it's best to do those in your player color do others know who drew them. But I could be missing an important common use case...what are you doing that it's causing you trouble with?