I've noticed when opening a solution in FileMaker Pro 14.0.2 on Mac OS X 10.10.5 that when closing a file that has multiple windows open the OnLastWindowClose script trigger doesn't always fire.
I have a OnLastWindowClose trigger that performs a simple script that navigates to a home layout and positions the window in the top left corner. This has worked reliably for v12 and v13, but with v14 if I have more than one window for the file open and close all windows the OnLastWindowClose trigger doesn't always fire. I can tell this is the case as the file opens to the last window and is not positioned in the top left corner of the screen.
I also have a OnFirstWindowOpen trigger which also doesn't appear to fire in this situation, i.e. when I open the file after having multiple windows open and the OnLastWindowClose doesn't fire the OnFirstWindowOpen also doesn't fire when opening the file again.