Recommended 

gk: 

Your application uses the appropriate style dialog box for the display of messages to the user. 

Optional 

gl: 

An information dialog box is used to display status, completion of activity, or other informative types of messages to which the user need not necessarily respond other than to acknowledge having read the message. 

Minimally, information dialog boxes should have an OK button so that the user can dismiss the dialog box. If there is additional information available about the situations under which the message is displayed or other references for the topic to which the message relates, then a Help button should be included. 

Optional 

gn: 

A question dialog box is used to ask questions of the user. The question is clearly worded to indicate what a Yes response or a No response means. The buttons displayed are Yes, No, and Help. Help provides additional information as to what the application will do in response to a Yes or No choice. 

Where possible, you should replace the label for the Yes and No buttons to make it clear what action will be performed as a result of choosing either option. For example, if the user has made changes to a document and has not saved these but has chosen the application's Exit option, you might display a question dialog box that asks, "Changes have not been saved. Do you want to save these before exiting?" The buttons should be Save, Discard, Cancel, and Help. These labels allow the more experienced user to click the correct button without having to carefully read the question and relate it to the button labels. 

Optional 

go: 

A warning dialog box is used to communicate the consequences of an action requested by the user that may result in the loss of data, system or application accessibility, or some other undesirable event. The dialog box is presented before the action is performed and offers the user the opportunity to cancel the requested operation. The buttons displayed are Yes, No, and Help, or Continue, Cancel, and Help. Help provides additional information on the consequences of performing the action requested. 

The use of Yes and No or Continue and Cancel depends on the wording of your message. The labels for Yes and No should be replaced as suggested previously. Continue may be replaced with a label more specific to the action that will be performed. 

Optional 

gp: 

A working dialog box is used to display in-progress information to the user when this information is not displayed in the footer of your application's window. The dialog box contains a Stop button that allows the user to terminate the activity. The operation is terminated at the next appropriate breakpoint, and a confirmation might be displayed asking whether the user really wants to stop the activity. The confirmation message might state the consequences of stopping the action.