I just started using ZBrush and it’s taking some getting used to, so bear with me as I hope this is an easy one. I’m running 4r6 on Mac OS X. I was working on a tool and instead of hitting the F key to get my object centered back in the screen I accidentally hit Command+F- it made my entire screen fill to the main color in the swatch palette. First off what exactly is this function? I did a search on the ZBrush shortcut doc and nothing came up. Second I went to undo, and I got my object back, but edit mode was disabled and I had no idea how to get edit functionality back for my tool. I eventually just opened a new doc and reloaded my tool- I’m assuming there’s an easier way?
It’s the shortcut for Fill Layer - the canvas is filled with the current color and material. It’s part of ZBrush 2.5D painting capabilities rather than 3D modeling. You can clear the canvas by pressing Ctrl+N. If you had a model in Edit mode then you’d need to redraw the model and press T to re-enter Edit mode.
Note that ZBrush doesn’t distinguish between Cmd and Ctrl for MacOSX. The list of shortcuts will have Ctrl+F rather than Cmd+F but they both have the same result.
See here for the differences bewteen 3D modeling and 2.5D painting:
http://docs.pixologic.com/getting-started/basic-concepts/
Thanks Marcus- weird I actually did a search of “+F” on the ZBrush Docs shortcut page but it didn’t pull up that command- I found it this morning though 
Thank you for the help!