See this comment, and the rest of the thread which regards a similar bug (possibly same root cause) that was affecting Dolphin context menus: https://bugs.kde.org/show_bug.cgi?id=314575#c17 I find this to be reproducible at the moment, but if it's like the bug Dolphin was experiencing, it may come and go depending on the time of day/mood of the network/position of the stars/etc. When you get it, it tends to stick around until at least re-logging in, though. Reproducible: Sometimes Steps to Reproduce: Right click on the window title bar, then mouse over "Activities". Actual Results: Congratulations, you now can't use your desktop for about a minute, evidently until something times out. For what it's worth, I'm in strong agreement with Frank's sentiment expressed in the linked thread: operations that could potentially block the UI have no place in a context menu. Personally, I think that starting with a "Loading..." placeholder (or similar), then updating the menu once the operation is complete, would be the best solution.
Actually libkactivities is supposed to cache those values, thus avoid the dbus calls, meanwhile. *** This bug has been marked as a duplicate of bug 304626 ***
Ah. I was assuming that the values in question were of the type that couldn't be sensibly cached, but certainly that would be an even better solution if possible.