Desktop misbehaving since Apple upgrade

[Gone To Lunch]

I am currently using 10.13.6 and my desktop is misbehaving since I accepted the last auto upgrade from Apple.

I organise my DP using mission control to give me separate screens for each window, but now the desktop insists on putting everything in a new tab in the same window, instead of opening a separate window as before.

It also does this with pictures in Preview, even though I have ticked ‘open each file in its own window’

Also in Finder I have not ticked ‘Open folders in tabs instead of new windows’ and in mission control I have not ticked ‘Group windows by application’.

Also, when in DP, I notice windows do not close completely, eg when I close the mixer window the slider strips and or the wiper line remain. Also, when I open a plug-in, sometimes it now automatically opens it in a new tab, and then shrinks the mixer. I can get to the plug by selecting ‘move to a new window’, but of course it is irritating to have to do three clicks instead of the one as before.

And sometimes the screen simply freezes for a couple of seconds, but without the beach ball.

[mikehalloran]

Since it happened with an OS update, I'd be asking Apple Support. An OS upgrade is one of those qualifiers for a phone call.

[Gone To Lunch]

I have not been able to get through to Apple, as my serial no is not recognised.

But I have posted the question on their forum.

In the meantime I have re-installed 10.13.6 from last year, and the problems are still there ?

I am wondering is there something I can delete in my system preferences ?

[Gone To Lunch]

Problem solved.

In System Preferences>Dock :

'Prefer tabs when opening documents;' - when I set it to manual I got my normal tab+window behaviour back.

How it got changed, I don't know.