fixed-columns="true" does not show effect

[Chris75forumname]

How is fixed-columns="true" supposed to work? I cannot find any details. If I set this to true it doesn't show any effect. Expected behavior would be, the first column col0 stayed fixed when scrolling x. Extended functionality could be to keep a range of columns from the left fixed, like col0-col2 or so.

But I wonder what it is meant to do??