Since RC1 I have had frequent problems with highlight/middle-click not working. Often I can paste with Ctrl-V when middle-click does nothing.
The second problem is that klipper seems to get stuck, sometimes - possibly connected with the dbus bug? Anyway, when that happens I can't view the cliboard. Using System Activity I can send the Signal STOP, wait until I see it stopped, then send the Signal CONT. After that the clipboard content is visible and usable again.
Anne