When a RowLayout or ColumnLayout is used as a page in a StackLayout, and it is not the first page shown, it will not correctly fill the StackLayout the first time it is shown. The size will be corrected if the StackLayout is resized or if its currentIndex is changed to another page and back again. This appears to only affect layouts, not other items. This issue did not occur in 6.7.0. A qml file that demonstrates this bug in Qt's provided qml preview tool has been attached.