I just installed a desktop machine with brand new Ubuntu 26.04.
One of the things I missed was the possiblity to paste selected text by pressing the middle mouse button.
The fix for Ubuntu default desktop (Gnome) is as easy as:
linux # gsettings get org.gnome.desktop.interface gtk-enable-primary-paste
false
linux # gsettings set org.gnome.desktop.interface gtk-enable-primary-paste true
Of course the first command is only needed to check the default setting (which is false). Changing that to true makes paste work immediately.
For other desktop types you might have to change the setting a little. For Mate desktop this should work:
linux # gsettings set org.mate.interface gtk-enable-primary-paste true
