An intermediate pane inserted into a door-support is positioned between an outer and an inner pane and its position between them fixed by at least one detent (27). The intermediate pane is detachably fixed in the oven-door by means of the detent and is released towards the inner or outer pane by the detent which is located in the space between the inner and intermediate panes. The detent is joined to a bit gauge (29) by an elastic connecting-arm (31). the intermediate pane is pressed against the detent by at least one spring (47).
