Your code is inside out.
While loops don't belong in case structures. Case structure belong in while loops. You don't have any overall while loop that keeps your code running until you press stop.
Also several of your stop buttons are hidden. You shouldn't have multiple stop buttons to stop individual loops. It is a user interface nightmare to hit a stop button and not have the code stop because you didn't hit the right combination of stop buttons.
Generally, tab controls aren't used to drive case structures. They are only used to organize the controls into different pages.
You should rearchitect your program into one that uses a state machine architecture. Since you are basically looking at a series of events: Intialize, Idle, Start, Run, Stop, Shutdown, the series of eventsand when you transition from one to another would be controlled by what buttons get pressed
