SUMMARY Quickly selecting/deselecting multiple .desktop files on the desktop using the selection rectangle causes lag and throttling, especially if at least 10 (the minimum number may vary) are being selected in a row or column. STEPS TO REPRODUCE 1. Add at least 10 different .desktop files (symlinks) from the application launcher by right-clicking on an each app and selecting "Add to Desktop". 2. Align all the files in one or multiple rows/columns on the desktop. 3. Hold the left mouse button and quickly move the cursor until they are all selected, then quickly move it backwards while still holding the button to deselect them one by one. 4. Repeat the previous point multiple times to cause lag. OBSERVED RESULT You should notice visible lag. I also get this message from the system log: "systemd[1]: Looping too fast. Throttling execution a little." EXPECTED RESULT There should be no lag at all. SOFTWARE/OS VERSIONS Linux/KDE Plasma: KDE Plasma Version: 6.1.5 KDE Frameworks Version: 6.5.0 Qt Version: 6.7.2 Kernel Version: 6.9.12-3-MANJARO (64-bit) Graphics Platform: Wayland ADDITIONAL INFORMATION I'm using a hybrid graphics laptop (Intel + Nvidia). Operating System: Manjaro Linux Processors: 12 × 13th Gen Intel® Core™ i5-13420H Memory: 15,3 GiB of RAM Graphics Processor: Mesa Intel® Graphics
This issue may be related to https://bugs.kde.org/show_bug.cgi?id=489894
(In reply to alt from comment #1) > This issue may be related to https://bugs.kde.org/show_bug.cgi?id=489894 I was able to reproduce this bug too
Do any of the apps have large images set as their icons? If so, this is probably another manifestation of Bug 489894.
No, they are just ordinary icons, less than 100 kB
Hmm, OK. I can't reproduce it, unfortunately.
(In reply to Nate Graham from comment #5) > Hmm, OK. I can't reproduce it, unfortunately. I was able to reproduce it on a live USB of Manjaro, but I had to switch to a Wayland session because this issue doesn't happen with X11. I'll add a video as an attachment.
Created attachment 173927 [details] Video of the desktop lagging
Does it still happen in Plasma 6.2?
(In reply to Nate Graham from comment #8) > Does it still happen in Plasma 6.2? Yes, still there
Can reproduce with over 100 icons on my system. Probably the threshold at which it starts to happen is dependent on the hardware, and maybe secondarily the contents or mimetypes of the icons. Should be fixed with https://invent.kde.org/plasma/plasma-desktop/-/merge_requests/2628.
Git commit f7a92f7e65ac09cfd82a01835ac9f955c1b25744 by Akseli Lahtinen. Committed on 13/11/2024 at 12:51. Pushed by akselmo into branch 'master'. FolderView: Performance improvements for selections This MR has multiple changes, especially related to the "rubberband" (selection rectangle). - Use `Qt.callLater` for `gridView.rectangleSelect` to eliminate redundant calls. - This was previously called *every time mouse moved one pixel* - Clear a redundant mapToItem - `var cPos = mapToItem(gridView.contentItem, mouse.x, mouse.y);` needs to be only called during rubberband action - Update dragItem images after selection is done, instead of every time a delegate is selected - Instead of creating and destroying `selectionButton` in `FolderItemDelegate`, create it once and toggle its visibility These all should help with the performance related to selecting multiple icons by dragging the selectiong rectangle around them. M +13 -17 containments/desktop/package/contents/ui/FolderItemDelegate.qml M +26 -9 containments/desktop/package/contents/ui/FolderView.qml M +5 -0 containments/desktop/plugins/folder/foldermodel.cpp M +1 -0 containments/desktop/plugins/folder/foldermodel.h https://invent.kde.org/plasma/plasma-desktop/-/commit/f7a92f7e65ac09cfd82a01835ac9f955c1b25744
hey, this bug is still present in Plasma 6.3
In that case, it's actually Bug 469445. You can fix it yourself by deleting the `ScreenMapping` section in your `~/.config/plasma-org.kde.plasma.desktop-appletsrc` file and let it get regenerated naturally. *** This bug has been marked as a duplicate of bug 469445 ***
I don't think this is a duplicate of bug 469445, as I have deleted the ScreenMapping section of ~/.config/plasma-org.kde.plasma.desktop-appletsrc and the issue still persists (plus, I never had crashes, nor other slowdowns except this specific one). Moreover, as I pointed out previously in a comment, this bug doesn't happen while using X11, but only while using Wayland. So I think that this is a clear indicator that it must be something related exclusively to the Wayland-specific implementation.
Re-opening since the issue is still occurring in 6.3.0, even after the workaround FWIW I can't replicate this on git-master or 6.3.0 but as Nate said, it might be hardware dependent, using about 30 .desktop shortcuts