Users often request an ability to drag a row or column and have it switch with another so that they can quickly move information around. In google docs the ability to quickly drag a row and switch its position has seen it become very popular, In excel the function is achieved by a cut and insert paste which drops the row down below the cut row. The ALT key which works in the standalone does not work in the online version. Function not working in LOOLWSD 4.2.0 git hash:fafb01f or earlier (collabora office 6.2-3). Press and hold the Alt Key while dragging the header and nothing happens. The expected behavior can be seen here https://github.com/nextcloud/richdocuments/issues/783 Currently is does not work at all and I suggest it is a feature upgrade rather than a bug in the online version.
Sounds like a reasonable enhancement.