When I use composite transprency under e16, I can't right-click to configure desklets. It happens only with this new version : gnome-extra/gdesklets-core-0.35.2-r1. I was using gnome-extra/gdesklets-core-0.34.3-r1 without any problem.
Reassigned to gdesklets herd. Have you tried any other window managers? Can you left- or middle-click on them (the ones that respond to left-clicks, at least)? Does it work in e16 without transparency enabled?
It works with gnome and twm, there is no problems when I start 'xcompmgr'. However, when I start 'xcompmgr' in e16, there is no problem. It only happens when I select 'activate composite' through the e16 menu. I can left- and middle-click (to move it) but when I right-click, the desklets menu appears and disappears immediately.
Ok, I've found a new issue : it's not a gdesklets error, but a gtk error. I've the same right-click problem with liferea (a rss reader).
I have a similar problem with context menus. With composite transparency enabled under e16 context menus are disabled.