Merging the display_tickets, adding_tickets into one

[dat-adi]

Is your feature request related to a problem? Please describe.
Having the user click on two different icons for adding and displaying tickets might be a turn-off.

Describe the solution you'd like
Have the root of the window turn to adding_tickets when button is pressed requesting for it.

Describe alternatives you've considered
Another approach would be to make adding_tickets into frames, and merge it with display_tickets.
However, that would make for a very long piece of code.