# Edit

The Edit menu contains several features which are convenient for working on a project.

## Undo

This function allows the user to undo a changes made to the unsaved project. Changes made to the project are stored in a buffer, the size of which can be changed under Seg3D preferences. This function can be called using the shortcut CTRL/CMD+Z.

## Redo

Redo an operation on a project that was previously undone. This function can be called using the shortcut Shift+CTRL/CMD+Z.

## Copy Mask Slice

Copy a single slice from a mask layer which can then be pasted onto other layers. This function can be called using the shortcut CTRL/CMD+C.

## Paste Mask Slice

Paste a previously copied label from one slice of a mask label to all the slices of another mask label. This function can be called using the shortcut CTRL/CMD+V.

## Punch Through Volume

After creating new label data on a single slice of a mask layer, that label can be copied or “punched” to every other slice by selecting this option. This function can be called using the shortcut CTRL/CMD+P.