It turns out that I was maybe too enthusiastic last time. Removing all the applets but the taskbar does not makes my situation any better.
However, I think that I found a quite reliable trigger for the bug :) :)
In the notification tray, I have some auto-hide (for example, I want to see the state of Kopete, but not my keyboard layout selector). That tray has a small arrow that toggle "hide/extend". The fact to click on the arrow in order to extend the view triggers the bug. When I make the click, I instantaneously get X -> 70%, plasma-desktop -> 20% of CPU.
Unfortunately, the fact to re-hide does not fixe the situation. It is also quite sure that there are many other triggers.
BTW, one should change the description of the bug because it is impacting X as well (and, in fact, much more) as plasma-widget.
It turns out that I was maybe too enthusiastic last time. Removing all the applets but the taskbar does not makes my situation any better.
However, I think that I found a quite reliable trigger for the bug :) :)
In the notification tray, I have some auto-hide (for example, I want to see the state of Kopete, but not my keyboard layout selector). That tray has a small arrow that toggle "hide/extend". The fact to click on the arrow in order to extend the view triggers the bug. When I make the click, I instantaneously get X -> 70%, plasma-desktop -> 20% of CPU.
Unfortunately, the fact to re-hide does not fixe the situation. It is also quite sure that there are many other triggers.
BTW, one should change the description of the bug because it is impacting X as well (and, in fact, much more) as plasma-widget.