I love the new terrain panel as it fits the overall studio theme better, but there are a few annoying bugs(?) that need to be squashed.
In the old panel, the individual terrain tools would save their properties when switching to another tool. If you were to switch from Grow to Erode and you had the auto material identifier off, it would still be off when you came back. Right now if you switch to Erode from Grow and return to Grow, the auto material option becomes checked again.
Furthermore, if you switch to Add from Grow and then back to Grow, it checks the PlaneLock option because that tool has it on.
These will be fixed, thanks for reporting!