Hi, I'm really sorry, if this problem was discussed earlier, didn't find any topic.

I have TabControl and add Pages using TabControl.TabPages.Insert(index, TabPage)
If TabControl is visible, everything is ok, but if TabControl is hidden, TabPages are not inserted (TabPage object gets the TabControl as Parent, but won't be added to TabPages collection and won't be drawn, TabCount and TabPages.Count returns previous number before Insertion)
If i use TabPageCollection.Add method, everything is fine regardless if TabControl visible or not.

Please, need advice, i don't want to manipulate TabPages collection when TabControl is visible

P.S. i tested this issue with simple test app, just created TabControl, set visible to false,
inserted new TabPage at any position (in my case at the end), then called TabControl.Show() in other function, e.g. in ButtonClick event