Here is an interesting "bug" I discovered yesterday. My current system is openSUSE 13.1 with KDE 4.12.4, but I also checked on Fedora 20 with KDE 4.11.3 and I got the same result, so it affects some (maybe all) previous versions of KDE 4 too.
Steps to Reproduce:
1. Create a new file by right clicking free area of the Folder View widget > Create New > Text File... and name it whatever you want.
2. Repeat the first step and give a file the same name.
3. After that, "File Already Exists" dialog box should appear. Right click the Title Bar of the window > Move To Desktop > <current desktop>.
4. Switch to another desktop.
KDE Plasma Shell disappeared on all the other desktops.
Only the dialog box should do this.
I confirm that this bug is happening to me too. I am on KDE 5.4 . Everything works well for a couple of hours and out of the blue, when switching to virtual desktop 2 there is no desktop background, all the widgets and panels disappear. On Desktop 1 they're still there and working perfectly well, on desktop 2,3,etc they dissapear. You can still use desktop grid to drag windows to the black desktops and they work flawlessly and if there windows in those desktops before the black crash (I guess it's crash), they'll still be there, fine and dandy.
I'm including some info about my system:
Octopi Sys-Info Output: http://pastebin.com/btVaPDDD
sudo blkid: http://pastebin.com/e4tzLh8Z
sudo fdisk -l: http://pastebin.com/060sNYvp
sudo journalctl -b | grep plasma: http://pastebin.com/skvn3v9e
Is there something else you want to see?
Just checked and the bug is still present in Plasma 5.8.4. I've reported it almost 3 years ago in 4.12.4; many things changed since then; however, this bug is still present. Why does Plasma treat shell components as though they were normal windows? You can literally move application launcher between the desktops or on the desktop via Window Actions for Inner Window modifier key (which is Alt by default).
Here's a short demo of this:
It is really bad design. Shell components should be treated differently.
Update: So, I checked it again and desktop widgets no longer disappear, but the panels still do.
Can confirm this bug in:
Distribution: KDE neon Developer Edition - Stable Branches
Panel doesn't appearing on second desktop also after closing of file already exists dialog
So, a quick update: It's still present in 5.19.
Git commit 7a4cabf3287e82e7d1d6ba84b8b059ab470f9f42 by Marco Martin.
Committed on 06/05/2022 at 10:44.
Pushed by mart into branch 'master'.
QML version of the Desktop Grid effect
Replace completely the old desktop grid effect with a QML version.
Aims to feature parity and be a change as transparent as possible for the user.
Related: bug 433071, bug 452625, bug 443971, bug 437121, bug 452925, bug 437928, bug 452439, bug 288530, bug 450254, bug 450106, bug 447832, bug 449960, bug 416576, bug 441862, bug 444859, bug 445999, bug 422117, bug 404627, bug 435483, bug 420744, bug 435482, bug 427055, bug 429120, bug 427391, bug 409295, bug 294322, bug 356955
M +5 -0 src/effects.cpp
M +10 -5 src/effects/desktopgrid/CMakeLists.txt
D +0 -1571 src/effects/desktopgrid/desktopgrid.cpp
D +0 -186 src/effects/desktopgrid/desktopgrid.h
D +0 -32 src/effects/desktopgrid/desktopgrid.kcfg
M +6 -14 src/effects/desktopgrid/desktopgrid_config.cpp
M +2 -2 src/effects/desktopgrid/desktopgrid_config.h
M +68 -144 src/effects/desktopgrid/desktopgrid_config.ui
A +32 -0 src/effects/desktopgrid/desktopgridconfig.kcfg
M +5 -1 src/effects/desktopgrid/desktopgridconfig.kcfgc
A +342 -0 src/effects/desktopgrid/desktopgrideffect.cpp [License: GPL(v2.0+)]
A +108 -0 src/effects/desktopgrid/desktopgrideffect.h [License: GPL(v2.0+)]
M +5 -4 src/effects/desktopgrid/main.cpp
D +0 -26 src/effects/desktopgrid/main.qml
M +1 -0 src/effects/desktopgrid/metadata.json
A +255 -0 src/effects/desktopgrid/qml/DesktopView.qml [License: GPL(v2.0+)]
A +193 -0 src/effects/desktopgrid/qml/main.qml [License: GPL(v2.0+)]
M +22 -5 src/effects/private/qml/WindowHeap.qml
M +21 -3 src/libkwineffects/kwineffects.h
M +4 -1 src/libkwineffects/kwinquickeffect.cpp