well i did wanted the cplane to align with some curve drawn but just to rotate the actual plane like you said. A problem with placing the tool in the origin is that a lot of times you are far from it. Other problem i see is if you accidentally clic on some axis of the tool you change the rotation axis to something useless in the current view, you need to go to the 3d view and from there change the rotation axis to the original one. Whith this new "2D" mode i don't see any problem with the example you gave me of making a cross section.