I have the file system browser plugin enabled. I've also checked "automatically synchronize with current document". If I open a file, I can't use the browser plugin's up/parent folder button to navigate to the parent folder. I have to uncheck the synchronize button to get it working again. The previous KDE 4 behavior allowed this.

Setup:
1. enable filesystem browser plugin and open it as a sidebar.
2. add the parent folder button to the plugin's toolbar
3. enable automatically synchronizing

steps to reproduce:
1. Use the file system browser to navigating into a folder, say '~/foo/'
2. Open a file or two, say 'bar.txt'
3. (Possibly optional) open another file, change between their tabs in the main view in order to cause the plugin to kick off a sync.
4. Click the parent folder up arrow button.

(note: for step 3, when navigating locally I seem to have to flip active documents as described before the button 'breaks'. If I'm navigating remotely to something like fish:/myserver/foo then this step doesn't seem to be required and it breaks immediately)

Expected result:
The browser should go up a folder, from ~/foo to ~/

Actual result:
Nothing happens. I have to disable the sync option to navigate up again. Back/forward and entering into deeper folders still work.

Version info:
OS: KDE Neon current, 16.04 Ubuntu based?
Kate: 16.12
KDE Frameworks: 5.29
Qt: 5.7.0