//Adds a sphere
private void buttonAddSphere_Click(object sender, EventArgs e)
{
GameModel model = Collection.GetGameModelByID(Program.CurrentModelID);
PSphere newSphere = model.AddSphere();
comboSpheres.Items.Add(newSphere.ID);
Program.CurrentSphereID = newSphere.ID;
textCenterX.Text = "0";
textCenterY.Text = "0";
textCenterZ.Text = "0";
textRadius.Text = "0";
Collection.WriteFile();
}