The scroll bar of Pd's console doesn't work properly on Mac OS:
1. On the bottom. where usually the up and down-arrow buttons are located, there is only the up-arrow button
2. If you click on the scrollbar's cursor and drag it, the scroll bar cursor's movement are "out of sync" with the mouse cursor's movement. The bar's cursor tends to "drift" upwards compared to the mouse, and the offset is accumulated.
Pd Vanilla 0.42.6 on Mac OS.