Hi every One. In my DataGridView.Cellvalidating i raise a event (via a function in a Class) In a another Form i have a TabControl with 3 TabPage in this form i catch the Event and i delete the active tabPage. TabControl.TabPage.RemoveBYKey(MyName) --> When this line is proceed.. i re enter in my DataGridView.CellValidating. I used TabControl.TabPages.Clear it is the same issue. I dont have the issue if i delete only the tabpage not currently active. Why ?