The common way of copy+paste in linux is to mark some text, and then middle-click where it should go.
This has been broken in 1.6svn for some time. The problem exists in a LyX compiled 17.october, as well as today's LyX. Such pasting will occationally work, but almost never. Pasting within LyX is ok, but this means it is almost impossible to bring in text from other editors or webpages. The edit->paste menus fail the same way - nothing happens. Also, 1.6svn seems useless in that latex now chokes on simple things like URLs. Probably an effect of ongoing development. :-) Helge Hafting