P: KBSC [ F ] for full screen returns to regular view when second screen is active

Great to hear that devs are on the case!

I'll chime in with the same full screen issue: When using two monitors, F (full screen command) will momentarily show full screen on main monitor, but almost immediately return to normal view. If I return to single screen the F command works as normal.

I'm on Win 11 and the issue (bug) is new since 12.3 upgrade. It did not happen in 12.2.1

I'm running a single 32" monitor but work mostly with portrait aspect ratio images so I have plenty of room to spare in the horizontal direction. Since stick & stone I've used Lightroom in such a way that I have the "Secondary Display" window showing grid open next to the Ligthroom main window in my single display.

Since 12.3 update the Secondary Display window keeps closing constantly. Whenever I switch to some other app or even when Lightroom dialogs pop up (like when copying settings using the Copy button in Develop module) the Secondary Display windows closes and I need to Shift-G it back up again.

Anyone with the same issue? I don't know if same happens with dual displays.

In LRC 12.3, in the library module, with main screen showing the zoom view (E), hitting F enters and immediately exits the full screen view mode. (My secondary screen shows the grid, disappears from screen upon hitting F, and then reappears immediately...)

Since installing Lightroom Clasic 12.3 my second screen keeps turning off.  I keep selcting it and shortly afterwards whilst doing almost any action. it turns off.  Particulary true when I switch between applications. When I come back to lightrrom only one screen is active.

I'm running on Microsoft Windows 11 Home.

I have attempted to reproduce this on two different Windows systems (10 & 11) using the instructions found in this thread. I do not find behavior changed from previous versions. 

If you use the KBSC [Shift]+[ F ] instead (which is a 3 position toggle) does it behave better for you?

Plus one here. I have exactly the same problem. I just upgraded to Lightroom 12.3 and immediately full screen preview no longer works in dual screen mode (it briefly goes full screen when I press f and then back again). If I first press F11 to go single screen, it works fine. I like to be able to see the grid on my second screen when in full screen preview, so I'm looking forward to a bug fix update to address this.

Thanks all above for reporting here, at least I know it's not just me!

I'm having the same issue. I discovered that if you don't show the second monitor in LR (little monitor icon, bottom left above the filmstrip), fullscreen works as it should. As soon as you enable the second monitor it quits working.

I have just upgraded LR Classic to the latest version (12.3, Build 202304101834-a085245c). When I press "F" in Library or Develop modules, my picture only appears momentarily in full screen, then goes back to Library or Develop view. This is an intermittent problem. I haven't seen it in previous versions of LRc. I'm using Windows 10 64 bit, latest update.