If we go to "Monitoring" -> "Graphs", then by default we see that the filter is open. If we hide the filter and press F5, filter will be shown again after refresh.

If we go to "Monitoring" -> "Web", then by default we see that the filter is closed. If we open the filter and press F5, filter will be closed again after refresh.

In configuration section (e.g., "Configuration" -> "Hosts") filters keep their open or closed state after refresh.