I am (still) using SW2014 SP5.
Some time in the past month or two toggling Tree Display / Show Flat Tree View does nothing. At first I assumed it was a file-specific issue but now I am pretty sure it is system wide. Toggling gives no errors. Toggling results in the active check mark being applied. But the tree remains in nested view regardless. The workstation has been restarted any number of times.
Any suggestions are appreciated.