To customize a button on an existing user-defined toolbar:
- Click File > Options > Customize Keyboard Shortcuts.
- On the Toolbars tab of the Customise dialog, select the button you want to customise in the added list.
- Click Change Button
to display the Customise Button dialog. - Select Customise. The Modify option becomes available and a small thumbnail of the selected button is displayed.
- Click Modify.
- Use the bitmap editing functions on the Customise Picture dialog to edit the bitmap picture.