Hello,

Until this behavior is resolved, we can use the following workaround to correctly position the filter popup on a higher DPI.

public RadForm1()
{
    InitializeComponent();
    this.radGridView1.FilterPopupInitialized += RadGridView1_FilterPopupInitialized;
}

private void RadGridView1_FilterPopupInitialized(object sender, FilterPopupInitializedEventArgs e)
{
    RadListFilterPopup popup = e.FilterPopup as RadListFilterPopup;
    popup.MinimumSize = new Size(300, 300);
    popup.PopupOpened += Popup_PopupOpened;
}

private void Popup_PopupOpened(object sender, EventArgs args)
{
    RadListFilterPopup popup = sender as RadListFilterPopup;
    popup.LocationChanged += Popup_LocationChanged;
    popup.Location = new System.Drawing.Point(MousePosition.X, MousePosition.Y);
}
private void Popup_LocationChanged(object sender, EventArgs e)
{
    RadListFilterPopup popup = sender as RadListFilterPopup;
    if (popup != null)
    {
        popup.LocationChanged -= Popup_LocationChanged;
        Screen screen = Screen.FromPoint(new System.Drawing.Point(popup.Left, popup.Top));
        if (popup.Left + popup.Width > screen.WorkingArea.Right)
        {
            popup.Left = screen.WorkingArea.Right - popup.Width;
        }
    }
}

Regards,
Dinko | Tech Support Engineer
Progress Telerik

Hello Erwin,

There is a separate feedback item for the column chooser in HDPI. You can share any feedback regarding the column chooser behavior in HDPI in the other item so that the development team can consider it.

Regards,
Dinko | Tech Support Engineer
Progress Telerik

Hello Emanuele,

Upon checking the feedback item, it is still not planned for fixing. I have already informed our development regarding your reply I have increased the priority of the item. At the moment this item is planned for fixing, we will update the status of the item so that you can be informed.

Regards,
Dinko | Tech Support Engineer
Progress Telerik

Hello,  Josh,

Thank you for the provided feedback. If you have any specific steps that replicate any undesired behavior that can be added to this scenario, it would be greatly appreciated if you can share it us so we can consider it when addressing the item.

In addition, make sure that you cast your vote for the item in order to increase its priority. The more votes an item gathers, the higher its priority becomes. 

Regards,
Dess | Tech Support Engineer, Principal
Progress Telerik