Two days ago, I upgraded from F22 to F24. The dnf upgrade succeeded and
applications seem to work, but there's a new, serious desktop usability
I'm using a dual-screen setup (LVDS + external monitor), where I usually
set Primary dIsplay = external monitor. Moreover, I place the KDE Panel
also on the external monitor. When I do that and try to navigate through
the Application Menu (launcher with cascading popup menus) or when I
click / move over a desktop widget, the following happens:
- After a mouse left click on the KDE menu icon (left hand side of KDE
Panel), the menu pops up only after a delay of >= 1 second
- When the mouse pointer is moved to another item in a popup menu, the
focus visibly jumps from item to item, and a delay of at least 1 second is
added on every intermediate item.
- When I click / move over a desktop widget, the desktop reacts with a
delay of >= 1 second
The delay problem consistently disappears when I set Primary display =
Laptop Screen, even though the KDE Panel remains on the external monitor.
It's strange that the KDE Panel does not move to the Primary display -- I'm
likely seeing the following bug
Bug 1322724 - Plasma panel not on primary screen
in F24 as well.
Also, the delay problem typically reappears when I go back to Primary
dIsplay = external monitor. Only in two out of perhaps a dozen
logout-login cycles, I observed that the delay problem was gone, despite
the fact that I had Primary dIsplay = external monitor. This may indicate
some kind of race condition.
Since this was an upgrade, I also tried the following, but the delay
problem behaved the same:
- Remove the contents of ~/.cache
- Temporarily remove ~/.config, ~/.local and ~/.kde and login to KDE
- Login to KDE as another user
Any idea which component should be blamed or how to debug this problem?
I wish some KDE debug messages could be seen in ~/.xsession-errors (I
enabled the debug messages using kdebugsettings), but I don't see any of
the familiar messages - maybe something is broken with the KDE debug
messages as well.
IBM Zurich Research Laboratory
CH-8803 Rueschlikon, Switzerland