It seems my initial account is partially inaccurate. The issue does not appear with PDFs only, but I see it also with PNG files. It is unclear if it is tied to the length of the filename and/or the fact that it is a file type with preview.

Additional info:
- sometimes the extension lingers on even when scrolling, not only when entering another directory;
- the problem appears on two setups, one with Intel Integrated Graphics and one with AMD discrete GPU;
- both setups use fractional scaling.

Thanks for the bug report.

I am not able to reproduce on:
KDE Neon VM with Plasma 6.2.1 / Dolphin 24.08.2 with 100% or 105% scaling (single screen)
git-master Plasma and Dolphin with two screens - 100% (laptop) and 105% (external HDMI)

Could I ask you to upload a screen recording of the problem? That will provide us detail that will help investigate the problem.

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Created attachment 175523 [details]
Issue screencast

Indeed the issue is not straightforward to reproduce, but I bumped into it again. Here is a screencast.

Contrarily to my previous hypotheses it seems to potentially affect any file type.

Note also that the in this recording the "persistent" extension does not appear unless I first select the file. But in other occasions (same directory) the extension shows when I enter the directory.

Do you have any plugins for Dolphin installed (through Settings - Configure Dolphin - Context Menu)?

Created attachment 175847 [details]
Dolphin plugins

Here is a screenshot of my Dolphin plugins. This should be pretty standard on a Fedora installation.

I noticed that the glitch sometimes appears also when scrolling directories with a large number of files.

Thanks for the screenshots. I can see a few things that look like they were added via the KDE Store:

Compare Files (last updated 9 years ago)
Compare/Merge Files/Folders with KDiff3 (last updated 9 years ago per the store)
Create Audio CD with K3b (also Create data project, Create Video CD) - if this was installed via the KDE Store it was last updated 16 years ago

What I would suggest is to try disabling those three plugins temporarily, and see if the ghosting bug still happens. If it doesn't happen, try re-enabling the plugins one by one and re-testing.
If you re-enable a plugin and the ghosting still happens, that plugin may be the culprit.

Let us know what the outcome is.

(In reply to TraceyC from comment #8)
> Thanks for the screenshots. I can see a few things that look like they were
> added via the KDE Store:
> 
> Compare Files (last updated 9 years ago)
> Compare/Merge Files/Folders with KDiff3 (last updated 9 years ago per the
> store)
> Create Audio CD with K3b (also Create data project, Create Video CD) - if
> this was installed via the KDE Store it was last updated 16 years ago
> 
> What I would suggest is to try disabling those three plugins temporarily,
> and see if the ghosting bug still happens. If it doesn't happen, try
> re-enabling the plugins one by one and re-testing.
> If you re-enable a plugin and the ghosting still happens, that plugin may be
> the culprit.
> 
> Let us know what the outcome is.

I will surely try, thanks. Let me clarify that none of this have been installed through the KDE store. These come packaged with the corresponding software, at least on Fedora.

(In reply to TraceyC from comment #8)
> Thanks for the screenshots. I can see a few things that look like they were
> added via the KDE Store:
> 
> Compare Files (last updated 9 years ago)
> Compare/Merge Files/Folders with KDiff3 (last updated 9 years ago per the
> store)
> Create Audio CD with K3b (also Create data project, Create Video CD) - if
> this was installed via the KDE Store it was last updated 16 years ago
> 
> What I would suggest is to try disabling those three plugins temporarily,
> and see if the ghosting bug still happens. If it doesn't happen, try
> re-enabling the plugins one by one and re-testing.
> If you re-enable a plugin and the ghosting still happens, that plugin may be
> the culprit.
> 
> Let us know what the outcome is.

"Compare files" comes from Kompare. I have this only on one of my two machines. Problem appears on both.

I have uninstalled K3b and the corresponding Dolphin plugins are gone.

I have disabled the Kdiff3 plugin.

Yet the problem persists.

Well bummer. Thanks for going through that troubleshooting. I'll leave this open and hopefully someone else can reproduce the issue.

(In reply to TraceyC from comment #11)
> Well bummer. Thanks for going through that troubleshooting. I'll leave this
> open and hopefully someone else can reproduce the issue.

Thank you for helping. I am not sure why it is so hard to reproduce. The issue appears on two different PCs with very different hardware and graphics configuration (desktop with AMD GPU and laptop with Intel integrated graphics). It's also not infrequent when I browse my files regularly. I am surprised I was the only one to report this.

Maybe I will manage to share a directory that triggers the issue (but must find one that is light and without personal data in it).

I found a pattern that may make this reproducible.

> mkdir test-directory
> cd test-directory
> touch VfEsm_So_gMzlIKp_aMuwp-stElm_kMAIgPZ_uiI_USaGGz_FlmejDmXpHX_nYBRyu_30-04-2024.txt
> touch VfEsm_So_gMzlIKp_aMuwp-stElm_kMAIgPZ_uiI_USaGGz_FlmejDmXpHX_nYBRyu_30-04-2024.pdf

Now, enter test-directory with Dolphin and adjust the zoom to regulate the size of the icons until the two filenames show as follows.

The txt:
---
VfEsm_So_gMzlIKp_
aMuwp-stElm_k
MAIgPZ_uiI_US....txt
---

The pdf:
---
VfEsm_So_gMzlIKp_
aMuwp-stElm_k
MAIgPZ_uiI_US....
---

Now, here is the curious part: upon entering the directory, the pdf extension does not show, as per example. It is displayed on a *new line* in the filename following one of these two events (1) moving the mouse cursor from the directory panel to any of the Dolphin panels/bars (2) a mouse click on the empty space in the directory panel. Hovering the mouse on the files or even clicking on them does not trigger the appearance of the extension.

And it is exactly *that file extension* that lingers when switching to a different directory.

In summary, when Dolphin abbreviates long filenames:
- some file extensions are not displayed when they should;
- some events trigger Dolphin to display these extensions, but they are painted in the wrong place;
- when switching to a different directory, the extensions painted in the wrong place remain as ghosts until the window is repainted.

To reproduce it, I think one has to nail the correct combination of filename length and icon size.

Interestingly enough, going from the minimum to the maximum size of the icons with the slider or CTRL + scroll wheel results in Dolphin painting a "trail" of extensions along the way.

Additional info: being in the process of setting up a new laptop, I could 100% reproduce this on a clean freshly installed Fedora 41 KDE with Plasma 6.2.1. 

It takes just an empty files with a filename at least three line long and .pdf extension. As just described, a file with the same name but .txt extension seems unaffected.

The zoom-out / zoom-in makes the issue immediately apparent.

Thanks for your persistence in trying to narrow down what causes this bug. With the new details you provided I was able to reproduce this on Plasma 6.2.3 with Dolphin 24.08.3

The good news is that I am *not* able to reproduce this with Dolphin built with git-master (25.03.70). I tested with various different zoom levels. I also notice that the pdf extension is not dropped from the visible part of the filename. The filename is properly elided (as with the txt file). I also didn't see the other incorrect displays of the pdf extension you saw. The problem should be fixed on your system when Dolphin is updated to a version with the fix.


To reproduce with Dolphin 24.08.3
Preconditions:
- Create a test directory
- Files created as described above with touch commands in the directory
- Subdirectory created in the same directory


Steps:
- Open the test directory in Dolphin, set it to Icons view mode
- Zoom until the filenames show as in the last comment (On a 3440p display at 100% I had it at 176 pixels)
- Notice that the pdf extension is cut off from that file
- Enter the subdirectory, notice the .pdf extension appear briefly (for me it didn't stick until window repaint)