Exercise 4 Design Preview Simpleframe21 D Thement Decrement 1. Design the above frame 2. The number is initialized with the constructor of the frame to the first number in the combo box 3. Each time the combo box changes selection, the number changes to its current selection, and the text area is cleared. 4. The text area is updated each time one of the two buttons is pressed. If the button "Increment" is pressed, the number is incremented and appended to the text area. If the button "Decrement" is pressed, the number is decremented and appended to the text area. Exercise 4 Design Preview Simpleframe21 D Thement Decrement 1. Design the above frame 2. The number is initialized with the constructor of the frame to the first number in the combo box 3. Each time the combo box changes selection, the number changes to its current selection, and the text area is cleared. 4. The text area is updated each time one of the two buttons is pressed. If the button "Increment" is pressed, the number is incremented and appended to the text area. If the button "Decrement" is pressed, the number is decremented and appended to the text area