Paint brush requires large movement before stroke begins — Wacom Intuos M tablet

There is no such property as startDragDistance and I’m not sure how you got the effect. Anyway, the correct code snippet (from this post):

paint=slicer.modules.segmenteditor.widgetRepresentation().self().editor.effectByName("Paint")
paint.delayedPaint=False
paint.minimumPaintPointDistance=3