If the user has not permissions to see a file (e.g. /vmlinuz.old) and presses F3 (or Shift+F3)... Krusader opens a window and it's closed; however if F4 is pressed, then Krusader says "No permissions to edit this file.", which is correct. Note: Maybe it should be better that the error message was 'No permissions to edit the file "<name>".' to avoid confusions because e.g. the user might have incorrectly written the name.
On my side: 1. If Shift+F3 is used, nothing happens - no error, no opening and closing windows. It's a bug. 2. For F3, a correct error dialog is shown. I'll attach a screenshot.
Created attachment 113618 [details] error dialog for F3
> 2. For F3, a correct error dialog is shown. I'll attach a screenshot. Thanks, Nikita! I've tried pressing F3 on /swapfile and I see the same error message as you see, although pressing F3 on /vmlinuz.old I don't see any error dialog (just a window that is closed immediately). :-? Those are the permission of those files: $ ll /swapf* /vm* -rw------- 1 root root 545367040 abr 23 10:31 /swapfile lrwxrwxrwx 1 root root 30 jun 17 16:08 /vmlinuz -> boot/vmlinuz-4.15.0-23-generic lrwxrwxrwx 1 root root 30 jun 17 16:08 /vmlinuz.old -> boot/vmlinuz-4.15.0-22-generic $ ll /boot/vmlinuz-4.15.0-23-generic -rw------- 1 root root 8257272 may 23 19:49 /boot/vmlinuz-4.15.0-23-generic If I execute less /vmlinuz.old; less /swapfile; less /non_existant_file then I see /vmlinuz.old: Permission denied /swapfile: Permission denied /non_existant_file: No such file or directory but using F3 to see /vmlinuz.old (or /vmlinuz) I don't see any error message (at least using Kubuntu 18.04), does it happen to you, Nikita?
If I go to the /boot/ file and I use F3 to view all the vmlinuz* files, everything works as it's expected. Maybe the problem is in panelfunc.cpp, in if (!fileitem->isReadable()) { KMessageBox::sorry(0, i18n("No permissions to view this file.")); return; } // call KViewer. KrViewer::view(files()->getUrl(fileName)); // nothing more to it! because the user can't read /vmlinuz (nor vmlinuz.old) but `fileitem->isReadable()` says that it is readable (because it's only inspecting the symlink file)?
I confirm that if you press F3 on a symlink to a file which doesn't have read permission, nothing happens (I don't see any windows that are closed immediately).
Updated summary line.
This bug report is possibly related to https://bugs.kde.org/show_bug.cgi?id=396132
Thanks, Nikita!