private void btnAdd_Click(object sender, EventArgs e)
{
CategoryChoose categoryChooseForm = new CategoryChoose();
categoryChooseForm.Show();
this.Hide();
}
private void btnCreateNewLibrary_Click(object sender, EventArgs e)
{
Library.listOfFictions.Clear();
Library.listOfMagazines.Clear();
Library.listOfNewspaper.Clear();
Library.listOfScientificArticles.Clear();
Library.listOfTechLit.Clear();
CategoryChoose categoryChoose = new CategoryChoose();
categoryChoose.Show();
this.Hide();
}