taskbar

I've noticed whenever i press the windows button to access something else open while playing, my game freezes while my curser changes to a regular one but i'm not able to click anything or minimise the window. I tried to take a screenshot in game too and my screenshot captured the steam page...

Not sure how to describe this. It happens during fishing, when I'm madly clicking, and my hand moves just so, and the mouse drops down on or around the game frame edges or task bar. It closes and/ or crashes and I lose everything I've done that day. This has happened at least three times now...