Smplayer's default bar only has two buttons: Play/Pause and Stop. I like simplicity and the two minimal button approach is just fine because I do most "other" operations using the keyboard. However, there are occasions in which I am in need of using the mouse, that is why I had to personalize it to include my favourite buttons: Previous Next Loop and Zoom + Zoom -
Smplayer's zoom is probably one of the best damn things ever!!!