When Adobe updated Photoshop CC to v.19 Adobe also changed the way brushes work and you cant quickly turn your paint brush into an eraser anymore!
You used to be able to do it in one click by selecting the eraser and then selecting the last used brush shape!
Now Photoshop will switch back to the original tool as soon as you select it! (i.e the paintbrush)
Don't worry, in my Dtube tutorial video I show you a way around this so you can still use your paintbrush as an eraser.
The keyboard shortcuts I use in the video are
Clear Mode (eraser mode)
WIN: Shift+Alt+R
MAC: Shift+Option+R
Back to Normal Mode:
WIN: Shift+Alt+N
MAC: Shift+Alt+N)
Unfortunately, you are now out of luck with Mixer brushes and all other tool types, you will have to recreate your brush settings for those as there is no longer a way to convert paint brush settings into other tools. Let's hope Adobe fixes this soon!
Any questions just let me know!