Drag'n'drop in lists grabs wrong item

[humdinger]

This is hrev52080, 32bit

Reproducible in WonderBrush:

• Create a number of objects
• Select the 1st object
• Now drag'n'drop the 3rd object anywhere, for example to the end of the list

Instead of the item ou clicked on, the current selection is moved. Example avi attached.

I suspect hrev52062... ?

[humdinger]

d'n'd items in list

[jscipione]

I can attest to drag and drop in Appearance preferences colors list code is working correctly. It drags out the clicked on list item and drops onto the dropped item. This is most likely a bug in WonderBrush caused by the change in behavior to ListViews to make them do stuff on MouseUp instead of MouseDown. Wonderbrush may be making some sort of assumption about the item use on MouseDown and MouseUp that we have broken. Still, this may be a bug we should fix in Wonderbrush code rather than going back on our ListView changes.

[humdinger]

QuickLaunch also has issues when d'n'd favorites.

Appearances doesn't behave quite correctly either. A dropped colour changes the selected item's colour well, not the one you drop it on. See attached avi.

[humdinger]

Appearances d'n'd

[jscipione]

hmmmm are you sure you're not on Haiku previous to hrev52090? because that looks a lot like the pre-hrev52090 behavior of setting the currently selected color on drop instead of the post hrev52090 change of selecting the color you dropped on to.

[humdinger]

Right. As the ticket says, I'm on hrev52080. Guess I'll have to somehow try to fix QuickLaunch. Wonderbrush being closed-source will have to suffer the change.

[jscipione]

Well in that case the Color ListView is behaving as it should.

[humdinger]

Locale shows the same behaviour as WonderBrush.

[jscipione]

It may be something we're doing in ListView is not quite kosher and needs adjustment. Like we may have to save a piece of data in MouseDown and then use it in MouseUp kind of thing.

[closequarters]

So jscipione just did my own testing, and can confirm that Wonderbrush isn't working as one would expect, but that Appearance and Locale seem to be working. This is on the latest nightly hrev52112.

However I'm concerned we keep seeing so many problem reports related to the ListView change, so I'm going to spend a little time looking over the code again, and see if any solutions pop out at me.

[jscipione]

Unfortunately it is probably a bug in Wonderbrush perhaps similar to the one in Vision not calling its inherited class method in MouseUp or MouseDown. :(

[closequarters]

humdinger, I created a pull request for QuickLaunch to fix the drag and drop in the MainListView. The key was to use the index of the dragged item, not the index of the selected item. See ​https://github.com/humdingerb/quicklaunch/pull/21

I also spent some time thinking about how we could make sure this works with some of these applications like Wonderbrush that are breaking but so far I haven't come up with a way we can do that without also breaking the multi-select drag and drop that was resolved in #9190

[humdinger]

Thanks, David! PR merged. :)
Since I stole much of that code from Locale IIRC, it may be the same issue there. Wanna take a look?

[closequarters]

humdinger, I tested Locale last night on the current nightly but didn't see any drag and drop issues. (Indeed, Locale is where the multi-select drag and drop fix was tested in the first place). Are you seeing the issue where the "selected" item is dragged instead of the "dragged" item?

[humdinger]

I've attached another avi with the Locale issue (hrev52115).

[humdinger]

Locale prefs

[jscipione]

I can definitely see the problem in the Locale Pref code, it is assuming that the dragged item is a selected item and that is not a valid assumption. The bug needs to be fixed in Locale Prefs to use the index of the dragged item instead of the index of the selected item and then to only include the rest of the selected items if the dragged item is selected (which it may not be).

[closequarters]

Locale issue, as well as WonderBrush and QuickLaunch issue should be solved by new patch posted in #9190 (​https://review.haiku-os.org/#/c/haiku/+/343)

humdinger, the new patch should still work with the PR you merged the other day.

[waddlesplash]

And now merged.

[humdinger]

Thanks very much David. I've built an image with your patch (if only I knew waddlesplash would merge so soon... :) ).

I can confirm, it's working nicely now! Even old WonderBrush and Quicklaunch (even before your PR), as well as multiple-items d&d. Nicely done, thanks!