This function will simply unsmooth all selected edges.
Following parameters will be set to 'false':
- smooth
- soft
- hidden
This may also be helpful to make all elements visible, which are connected to a selected element (doubleclick and unsmooth).
With the '
collect to layer' - function you can then move 'lost' elements (it happens sometimes, doesn't it

to a desired layer and make them visible again (no searching through off-layers necessary anymore).