Effects of Modifying a Base Form's Appearance
In the course of application development, it is often necessary to change the appearance of the base form from which other forms in the project (or in other projects) are inheriting.
At design time, changes to the base form's appearance (be it the setting of properties or the addition and subtraction of controls) are reflected on inherited forms when the project containing the base form is built. It is not sufficient to simply save the changes to the base form. To build a project, choose Build from the Build menu.
Modifications made to the base form at run time have no affect on inherited forms that are already instantiated.