Up to R2019b, app designer don’t have this feature,
It is because if you click on the selected item, no event will be triggered. Therefore, we could say only single click is allowed under this limitaion.
You can use button to replace list box. [toggle button group will behave same as list box, so you could not use this], use the 'normal' button for this.
For example :
Step 1 : For example : 3 selection: Create 3 button
Step 2 : Create callback function for each of them (it is a bit tedious, I have 3 button, then I have 3 callback function)
Step 3: Create private function click
Step 4 : here you go:
(Single Click the button, it turns blue)
(Double Click the button, it turns red)
You might have further question about ‘how’and ‘where’ could you put your algorithm:
You could put your algorithm in the click function