Comment 2 for bug 906794

Works as expected in Inkscape 0.47,
in Inkscape 0.48.0 and later version (including current trunk) the switcher symbol (circle with arrow) for the path effect parameters is missing (new node tool), only the tiny diamond knot is displayed.

Note: if the path effect is applied to an individual path, one can still grab the tiny diamond (on top of the first crossing) and drag it to another crossing. Clicking on it will switch the type of crossing.

Editing the knot path effect for groups no longer works in 0.48.x and trunk.