"If an item within a Row is not visible, or if it has a width or height of 0, the item will not be laid out and it will not be visible within the row. Also, since a Row automatically positions its children horizontally, a child item within a Row should not set its x position or horizontally anchor itself using the left, right, anchors.horizontalCenter, fill or centerIn anchors. If you need to perform these actions, consider positioning the items without the use of a Row."
Reference, from QtQuick Row documentation:
"If an item within a Row is not visible, or if it has a width or height of 0, the item will not be laid out and it will not be visible within the row. Also, since a Row automatically positions its children horizontally, a child item within a Row should not set its x position or horizontally anchor itself using the left, right, anchors. horizontalCente r, fill or centerIn anchors. If you need to perform these actions, consider positioning the items without the use of a Row."