I have had to exit and restart the Bloom R1 version several times over the last several days because it simply stops saving my changes to my org. It the Controller & Helper min-tabs seem to always have the 'modified' asterisk even if they are being saved. But after a while, it quits pushing my changes altogether.
Also, I'd like a way to hide the Lightning Preview. I have yet to get it to work and it is just as easy for me to simply refresh my browser window.