Good time. If you go to settings... Preferences -> LXQT Settings -> LXQT configuration Center -> Openbox Settings.
It will be impossible to resize and close windows. How can I fix this ? Thank you.
I can confirm.
Delete ~/.config/openbox/rc.xml, then logout and login. It's probably because LXQt or OB has changed something in the way they read the settings.
It really works. After logging in, Clearlooks becomes the default theme, and in the future it works without complaints. Thank you.