Thanks to all who replied, indicating some sort of local problem.
Today, middle-click pasting from LyX to xterm works fine for me too. I don't know what happened, but I upgraded arch linux earlier today. Maybe some very temporary windowing bug got squashed.
This is good. I use ctrl+c and v only when I use the keyboard to make the selection and move around. Typically when cutting & pasting within a LyX document. It is faster when I don't have to reach for the mouse.
I use the middle mouse button when I use the mouse to select, and that is more common. Especially when copying between programs, when I need the mouse to switch focus anyway. (Forget alt+tab with more than "a few" windows.) When one is used to the ease of middle clicking, reaching for the keyboard takes way too much time. And not all apps use the same cut/paste keys. Using a right-click menu is even worse. The hassle of bringing up a menu and locating the right choice when I already had my finger on the mouse button that always do the right thing. I feel pain when I see beginners bringing up cut/paste menus on linux because they're used to such cumbersome ways from windows.
Helge Hafting
