How to make the popup resizable?

Set the FormBorderStyle of the PopupControlContainer’s parent form to the appropriate style.

Do that in the PopupControlContainer’s BeforePopup event handler. You have to do this as late as in the BeforePopup event handler because this is the earliest the PopupHost will be non-NULL.

C#

private void colorUIPopup_BeforePopup(object sender, System.ComponentModel.CancelEventArgs e)

{

    // Make the popup host's border style resizable.

    this.colorUIPopup.PopupHost.FormBorderStyle = FormBorderStyle.SizableToolWindow;

    this.colorUIPopup.PopupHost.BackColor = this.BackColor;

   // Necessary to set the host's client size every time, especially since the popup's Dock style is set to DockStyle.Fill.

   if(this.colorUIPopup.PopupHost.Size.Width < 160)     this.coloruipopup.popuphost.size = new system.drawing.size(160, 176);

   // so that the popup container will fill the entire popup host when resized.

   this.coloruipopup.dock = dockstyle.fill;

}