Exit Design Mode Toolbar

Removed in 2007
Clicking on a control when in this mode will fire the corresponding events and any code associated with it will run.

Design Mode

There are actually two modes available, "Design Mode" and "Run Mode".
Design mode allows you to work with the control without actually firing any events.
This is the mode that allows you to change the size and location of your controls.
The controls can only be moved, resized or deleted when in Design Mode.
As soon as you select a control from the toolbar you will be automatically placed in Design Mode.
This button changes to Exit Design Mode when you are in design mode.
To trap any of the events the necessary Event Procedure must be placed in the Worksheet Code Module and not in a general Code module.
To add an Event to one of these controls, just double click the control while in Design mode.
You can add a different event by using the procedure drop-down box in the top right of the Code window

Run Mode

Every time you select a control with your mouse it assumes that you want to use the control.
Clicking on a control when in this mode will fire the corresponding events and any code associated with it will run.