STEPS TO REPRODUCE
1. open a text file in kwrite (not kate)
2. settings -> configure -> behaviour -> set 'limit number of tabs' to '1' -> ok
3. file -> new
a new empty document is started in the same window and the old document disappears. But is still open.
With max tabs set to '1' I expect a new kwrite window to be opened.
KDE neon 5.26
KDE Plasma Version: 5.26.2
KDE Frameworks Version: 5.99.2
Qt Version: 5.15.7
This setting works as intended but I see the point that it would make sense to be able to configure some SDI like behavior.
*** This bug has been marked as a duplicate of bug 458621 ***