Tradingsim QA test #1

This simple application is a calculator, written on purpose to test QA engineer skills. There are 2 actions: square root and squaring, which are supposed to work in a common way. Please test this application and come back to me after a while (not earlier than 10 minutes: please take time to think) to tell me what's wrong with this app. Time is not a factor here, so please don't hurry.

Type the value, then pick the action.