This method is used with a variable of the WINDOW data type to clear a window previously opened by ui.Window.Open() or by ui.Window.OpenWithForm() methods:
variable.Clear()
If you use the method to clear the window containing a with form, the form will become invisible but won’t be closed.
If the form was opened by the OPEN FORM statement or ui.Form.Open(), it can be easily redisplayed by the DISPLAY FORM statement or ui.Form.Display().
If the form was opened together with the window - ui.Window.OpenWithForm() - and was cleared from the window, it cannot be redisplayed.
ui.Window.clear() accepts no arguments and returns no values. It clears the window associated with the WINDOW variable it is used with regardless of which window is the current one.
CALL win_var.Clear()