This improved version of a Notebook has the following improvements:
    - improved design
    - Tabs of notebook not resizable
    - Menu on tab when right-clicking, the posibility to add extra functions to it
    - Current tab-menu include: Close tab function, Close all tabs, Close others
    - Close tabs with middle-click on or by clicking the "close" button on each tab
    - Visible hover on tabs and on the closing button
    - Scrollbar to navigate through all tabs easly 
    - Posibility of using the mouse-wheel to scroll