4.7. Undo and redo<br>

## 4.7. Undo and redo

The program features a multi-level undo and redo system. You can undo and redo almost any operation performed on the project.

¨ To undo the last operation select “Edit / Undo” (Ctrl+Z, ).

If the last undo operation was unnecessary, you can restore the previous operation by performing the “redo” operation.

¨ To restore the undone operation select “Edit / Redo” (Ctrl+Y, ).

Undo and redo has a multilevel structure. You should, however, remember that after undoing an operation and then performing other operations on the project (changing data, placing a component), it is not possible to redo the undone operation. This is because the status of the project has changed and the operation to be redone may, for instance, apply to non-existing components.

The number of possible undo operations depends on program settings and specifications of the computer. The need to change the settings may result from the fact that the undo and redo functions require saving of the project in memory after each change.

¨ To change the settings of “Undo” and “Redo”:

1. Select “Options / Settings”.

2. Select “General” tab.

3. Specify the required value in the “Undo options” field.

Depending on hardware configurations, you can impose some restrictions on the number of operations stored in the memory:

- no restrictions,

- restriction on the number of operations stored,

- restriction on the size of memory occupied.

The default setting is maximum 8MB of memory. In most of the usual cases this is sufficient for much more than 20 undo steps. When you position the mouse pointer on the field with the number of megabytes (MB) allocated to the last project status, a hint appears with the memory size currently occupied for undo and redo operations.

There is an additional function “Undo and Redo saves screen position”. When this option is checked, then on undoing or redoing the displayed part of the drawing and the scale of the drawing are changed.