C＃winform应用程序中的UserPreferenceChangedEventHandler是什么？

I found some of my winform application controls, such as DataGridView and ToolStrips, are referred to by UserPreferenceChangedEventHandlers. I have no idea what setting of the controls will generate such references and why such references keep my control alive in memory. How can I remove such references from that event? Thanks.I found some of my winform application controls