Where are you using this function and which way are you using to set your in and out points?
Even if you're working in the Clip Monitor, there are several ways to set the in and out points.
I use in- and outpoints in Windows at Premiere Elements in clipmonitor with
I and O or the respective buttons in the monitor. But it does not react.
That is correct. In the Clip Monitor you can set the In and Out points by either dragging on the ends of the "live" area on the little timeline or by setting the playhead and clicking the Set In or Set Out buttons.