Tom,
Screen shots really WON'T help here as when you invoke the COPY>PASTE ATTRIBUTES command, via keyboard OR menu, doesn't bring up the Paste Attributes window.
I'm on an iMac 27" with 12GB of RAM, running Lion (10.7.5).
I CAN give you a typical example of what happens though…I tweak audio settings on a specific clip (e.g. volume, pan, set noise reduction, etc.) . THEN I select the clip I've tweaked, and choose COPY, then select a subsequent clip to which I want to apply the SAME audio settings and choose PASTE ATTRIBUTES.
SOMETIMES the window comes up, SOMETIMES it doesn't. SOMETIMES it will come up 2-3 times and then suddenly it WON'T come up anymore. VERY frustrating.
I CAN use PASTE EFFECTS, which accomplishes the same thing, BUT obviously if I've applied a VIDEO effect to Clip 1 that I DON'T want applied to Clip2 - this method won't work, and stuck tweedledumming and tweedledeeing with audio settings again.
This bug REALLY wrecks the fluid, creative workflow inherent in FCPX! Apple - PLEASE FIX!