R:BASE supports two types of windows: modal and modeless. Modeless, or non-modal, windows are used when the requested information is not essential to continue, and so the window can be left open while work continues elsewhere. Modeless windows are initiated in R:BASE using MDI (Multiple Document Interface) as a setting and command syntax parameter. Modeless forms let you shift the focus between the form and another form without having to close the initial form. The user can continue to work elsewhere in any application while the form is displayed. Modeless forms are harder to program, because users can access them in an unpredictable order. You have to keep the state of the application consistent no matter what the user does. Often, tool windows are shown in a modeless fashion.
The R:BASE "Find in Files" utility, accessible from the Utilities menu bar, is an example of a modeless dialog box.
A modal window must be closed before you can continue working with the rest of the application. Dialog boxes, launched using DIALOG or PAUSE 2 USING, are examples of windows that display important messages which are always modal.
