A custom toolbar button can invoke a menu. For example, to access a summary statistics menu from the toolbar, select the pull down menu:
Tools > Toolbar > Add a Button
Fill in the dialog box with the desired button number, color, a label, a message, and the command: menufile("menus\statsum.men") then click OK. A button will appear on the toolbar. Move to a Window that contains a series, and click on the "Stats" button. The summary statistics for that series will be displayed.
Alternatively, use the TOOLBAR command to place the button on the toolbar. The example presented above would use the following command: