I've had this issue for a while and have looked all over for a solution. Ever since I upgraded my iMac to High Sierra I've been having problems with multiple desktops. I have Desktop 1 set as my personal space, Desktop 2 as my business space, Desktop 3 as Lightroom, and Desktop 4 as Photoshop. I use to easily swipe between these workspaces with my mouse. Since updating to High Sierra no matter what desktop I swipe to it randomly automatically snaps back to the desktop I have Lightroom on. If I want to use Chrome in Desktop 1 or 2 I have to swipe to it, and quickly click the page so it doesn't snap back to Lightroom. I'm up to date on OS and Lightroom. HELP!!!