Specs: iMac 27" (Late 2012) running latest OS X Yosemite (10.10.3) with dual display set up (second display is an NEC PA271WP) and latest LR CC 2015 Edition.
My LR workspace layout has long been Full Screen + Menubar view on the NEC (Window --> Screen Mode) and Loupe/Normal on the iMac (Window --> Secondary Display --> Show --> Loupe - Normal). I would place the Loupe/Normal window on the iMac and it "anchor" to that display as the Secondary Display, leaving the NEC entirely for LR in full screen mode.
Since updating to LR CC 2015, the Secondary Display window won’t stay anchored to the second display (iMac) when I leave/return to LR ... it relocates to the same display as Primary Window (NEC).
Here's a screen shot of what happens whenever I return to LR from another app. I'll move that secondary window to the other display, and it'll stay there so long as I'm in LR, but if I switch apps ... it'll look like this again when I return.
I’ve tried all modes from Grid to Survey, and changed the Primary Display window from Full Screen to Normal, all with the same result: The Secondary Display always reverts to overlaying Primary Display content as shown above.
No other settings have changed from LR5.x to LRCC2015, and I’ve gone back through settings for both LR and the iMac to see if there’s anything that changed during the update without me knowing. Don’t see anything.
This is really annoying.
I’ve tried creating new Places or Spaces or whatever Apple calls them, with dedicated Desktops just for LR work, and it still reverts from proper dual display layout to both on same screen.