Generally, I can copy and paste key frames (keyframes) from one clip into another in the Effects Control panel with no problem, however, somewhat randomly, certain target clips won't accept the paste (and the paste option is grayed-out in the Edit menu). So far, I've only encountered the problem with windows' bitmap images, but, oddly, it's not uniform across all bitmap images -- some will accept that paste and some won't. Also, I've only had PP CS4 a short while, so I'm not confident that it's a bitmap-only problem.
I'm pretty sure that it's not my copy/paste procedure. I'm following the manual procedure exactly (expanded properties and all), but certain target clips just won't accept the paste. Also, there doesn't seem to be a correlation between the problem target clips and the ability to add key frames to them manually, nor does there seem to be a correlation as to "rogue" effects that might be causing the problem. OK, I'm stumped and all help, comments, suggestions, etc., will, of course, be much appreciated.
I don't ever recall encountering this problem in CS3. Thanks.