Create page form doesn't filter special symbols like slash or dot in page name

Follow this steps to reproduce:

• Choose create new page from the menu
• Set the page name field to Main.PageWith/Slash

As a result the "Slash" page is created in the "Main.PageWith" space. This is unexpected because if you input just "Main.PageWith" then a page named "PageWith" is created in the "Main" space.