On 1920x1080 external monitor (my main monitor is 1366x768), Japanese UI looks too bad. http://i.imgur.com/UJDeEnb.jpg (For example "ツールのオプション(Tool Option)" overflowed and became "ールのオプショ". It's too ugly...) This problem doesn't happen with 2.9.11. Animation Beta. http://i.imgur.com/VlF4LDy.jpg Reproducible: Always I guess this bug happens because application system font to Japanese UI is broken in 3.0.
We don't do anything different, so if a different font is selected, I suspect that it's a Qt5 issue.
What version of Qt is used with 2.9.11 and 3.0.0?
Krita 2.9 uses 4.9, Krita 3.0 5.6
I'm afraid we just cannot do anything about this; it's in the hands of Qt.