When I double click a PSD file on my desktop and then go check email or use another program, Photoshop opens in the background, but the file won't open until I switch to Photoshop. No matter how long I'm doing other things, the file only loads once I'm looking at Photoshop. This sort of defeats the value of multitasking. In the past Photoshop behaved like all other programs: opening a file launched the program and loaded the file. I'm not sure which update broke this functionality.
During a chat with an Adobe tech they reset all the preferences (without asking or warning me) and it worked, once. I tried again this morning and it's back to the old behavior.
This is on a Mac Mini with 16GB of RAM, latest version of MacOS and latest update to Photoshop CC 2017.