We find here various commands.
This directive tells if a given dialog is enabled or not. The back-end only send this directive to change the state of a dialog. A disabled dialog is not clickable. It may have a special appearance (gray out) and a special mouse cursor, showing it is inactive.
A dialog generally becomes inactive when an associated sub-dialog is presented. There is a modal relation between the two. Until the user quit from the sub-dialog, the original dialog is not listening. Disabling the dialog make this obvious for the user (mouse click have no effect).
The dialogid is the path of the dialog (main-0.form.dialog1). It is possible to effectivly disable sub-areas of a larger dialog. This is generally done for MDI like application using several notebook page to present various dialogs.
The state is either 0 to disable the dialog or 1 to enable it. A newly created dialog (Form, Mainform) is enabled by default.
This is a hook to let the front-end insert its own preference menu in the menubar. This is only sent while creating the menu bar generally just before sending the help menu bar.
This either show a mainform or hide it. val may be either 1 to show it or 0 to hide it.
This may be used at any time on a form to toggle its presentation on the screen. In general, this is used in combination with the $nopopup=1 extra parameter sent with the End directive.
The End directive as the side effect of showing the form. The nopopup delay the presentation until the Show directive is sent.