After Compiz is installed in Kubuntu, there is no title bar in the window.

You can search for the methods to install the compiz and Nvidia drivers. And some solutions to the "no title bar" problem are as follows: sudonvidia-xconfig -- add-argb-glx-visuals-d24sudonvidia-xconfig -- add-argb-glx-variables Als -- compositesudoapt-getinstalldesktop-eff the method to install compiz and Nvidia drivers is searchable.

And some solutions to the "no title bar" Problem

The following is my solution under KUbuntu:

Sudo nvidia-xconfig -- add-argb-glx-als-d 24
Sudo nvidia-xconfig -- add-argb-glx-metrics Als -- composite
Sudo apt-get install desktop-effects

Then run
Desktop-effects is OK.