It's not generally a good idea to use the paint bucket tool at all. When testing it, I found that the only way to get good results with it was to decrease the width of the lines you are filling in to a very low number (I used 0.05) before using it, and then increasing the width of the lines back to 1 (or more) after the area has been filled in.Does anyone know how to fix this when I do paint bucket?
The left is an example of what happens when I try to fill in something like the right. Does it have anything to do with the stroke?
IIRC I had Treshold set to 5, Grow/Shrink to 0.30 and Close Gaps to None. You should also make sure that the lines are in a layer above the one with the color. The initial result will still be very sloppy and inaccurate, but since the lines are thicker than they were when you filled them in, the inaccuracies will be covered up.