Try to set the number of columns for the RadGridView to greater than 11230 columns, it throws "An item with the same key has already been added." exception. It does not happen when the code is run for the first time, but on any subsequent calls. Step to reproduce:
1. Create project with Windows form
2. Place RadGridView on form
3. Add following code:
private void Form1_Load(object sender, EventArgs e)
{
radGridView1.VirtualMode = true;
radGridView1.ColumnCount = 15000;
}
4. Run application multiple times and you will get an exception at some moment during start up. NO WORKAROUND