Could it be some threading issue?

Thanks, selecting from any image is useful, to avoid starting always from the top one. But should not enable the button until a check is done.

I'd say it is some half-implemented feature, probably. Could it be useful to navigate by keyboard and check/uncheck images, by using space, for example?

In D22256#492127, @davidre wrote:

I guess one drawback is that you have to reindex all the files when the sort mode is changed.

Is it more efficient from the performance point of view to have a QSortFilterProxyModel class per sorting method? I have a 6000 images case, would that be consuming compared to setting the sort class once according to the sorting method?

In D22256#491942, @davidedmundson wrote:

The fundamental problem with this approach is you only sort through the dirs correctly, but not the total across multiple paths.

i.e
If I have two paths dirA and dirB and want things sorted by date this patch will have all the images in dirA sorted by date, followed by all the images in dirB sorted by date.

So for those reasons I think the other patch addresses works a bit better handling it dynamically, also allowing us to get rid of one of the model instances.

Besides that, did you know that if there are no wallpapers, could be added one or more by drag and drop?
Image files could be added by drag and drop, but never appear, although they are in the list, where should be folders only IMHO.
They stay there, nothing happens, no background change on the desktop.
Also, if one folder is added, 'Apply' button pressed, then removed, after 'Apply', the background remains set to the last image, although I would have expected to have no image set as wallpaper.

Indeed, at should crash, but when is that string empty?
I can't crash mine, although inherits the same code.

Ha Ha Ha! I know! I have asked you about, remember?
Sometimes the actual build goes bananas and needs a reset.

In D22121#491369, @ngraham wrote:

Huh, in a VM everything works for me too. I wonder if there's some subtle issue with the fact that I'm running a custom-compiled Plasma at a different path on bare metal.

Added Reversed, DirsFirst/DirsLast, IgnoreCase, LocaleAware options.

In D22256#490558, @davidedmundson wrote:

This is awkward timing.

See D22121: [Image Wallpaper Slideshow] Allow setting of different sorting orders

Sorry