Once you have performed a design step in the Sketcher (e.g. adding a line), in the docking window Tool (here with current labeling Edit element), the corresponding input fields are displayed.

Anytime there is the possibility to manually select an element in the Sketch history or Sketcher, in order to call the dialog and to change parameters.

When clicking on the button Discard changes all changes are cancelled.

If the checkbox Automatically apply changes is enabled, each valid change is automatically saved (however, nevertheless can be undone [Delete step or Undo ]).

If the checkbox is disabled, an OK button displays and changes are only applied after clicking the button.