The issue has a misleading title. The issue occurs generally when hitting the ALT key. I confirmed with Firefox 23 on Ubuntu 12.10. Lately the unity menu integration does not come as an addon. So, the previous solution (to disable the globalmenu addon if ones has high CPU load) does not work.
I found another solution, which is not optimal, but solves the problem to a certain usable extent. The problem was that there were hundreds of bookmarks in the bookmarks menu and the bookmarks toolbar. Some of them were dynamic RSS bookmarks, which means that they kept growing by the time. So HUD had to index all these bookmarks. The solution was to move all the useless bookmarks from the bookmarks menu to the "unsorted bookmarks". The latter do not appear in the menu and therefore do not have to be indexed by HUD. After I did this, still HUD requires a little bit of loading, but it is much faster and, most important, does not halt the entire system. I still believe there is an issue with HUD here: the entire adventure with the hundred features indicates to me that HUD's indexing is sub- optimal: it keeps re-indexing the same things that have already been indexed before, probably there is no (sufficient) caching or so. Another possibility could be a limit on the number of the bookmark items being indexed by HUD. -- You received this bug notification because you are a member of DX Packages, which is subscribed to unity in Ubuntu. Matching subscriptions: dx-packages https://bugs.launchpad.net/bugs/968533 Title: Alt-tab to Firefox sends Firefox to 100% CPU; unity-panel-service to 80% CPU and hud-service to 20-80% CPU Status in Unity: Confirmed Status in “unity” package in Ubuntu: Confirmed Bug description: I've been seeing UI hangs after switching tabs in Firefox, and switching from other applications to Firefox. It can take 3-8 seconds to change *tab*. During this time the CPU is maxed out; typical output from 'top' during this period shows 'hud- service' and 'unity-panel-service' combined using about the same CPU as Firefox itself: 100 10.4 26:07.73 firefox 53 0.6 6:14.86 hud-service 38 1.5 6:42.14 unity-panel-service I suspect that the change is causing a (an inefficient) re-index related to updated menu structures. (Eg. something like the history menu, although I can't see what it is as don't currently have a menu bar). To manage notifications about this bug go to: https://bugs.launchpad.net/unity/+bug/968533/+subscriptions -- Mailing list: https://launchpad.net/~dx-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~dx-packages More help : https://help.launchpad.net/ListHelp

