Sway: Riot breaks drag-and-drop

[SwayUser]

• Sway Version:

sway version 1.0-rc1-285-ge4f1ffe6 (May 20 2019, branch 'master')

• Debug Log:

https://gist.githubusercontent.com/SwayUser/c9847cf499c769b308659c3d9fc601ed/raw/7bfb2531d5470c8cfe499be6c359765b40098f7c/gistfile1.txt

• Configuration File:

https://gist.githubusercontent.com/SwayUser/1632a5c2ab742dadc9f138f429185f59/raw/a9187576c57a13e82940a8db1dd7d85d5b5aacfa/gistfile1.txt

1. Install the Riot flatpak from Flathub.
2. Open Riot.
3. Open an image in eog (I did it with Nautilus).
4. Drag the image in Riot.
5. If it works, cancel and drag it again. Sometimes I also dragged the image directly from Nautilus.
6. Observe that there's a point where drag-and-drop stops working.

[emersion]

Once again, pointer state gets corrupted.

2019-05-21 19:37:10 - [subprojects/wlroots/types/seat/wlr_seat_pointer.c:418] Pointer grab serial validation failed: button_count=2 grab_serial=154 (got 193)
2019-05-21 19:37:10 - [subprojects/wlroots/types/seat/wlr_seat_touch.c:371] Touch grab serial validation failed: num_points=0 grab_serial=0 (got 193)
2019-05-21 19:37:10 - [sway/input/seat.c:349] Ignoring start_drag request: could not validate pointer or touch serial 193

[luispabon]

I've seen something I reckon is similar in Nautilus and Dolphin (running in wayland mode, in xwayland mode the problem doesn't happen). After a while dragging files stops working - it's not that drop has no effect, it's that click & drag literally doesn't drag anything, at least not visually. I'm collecting logs to see if reappears.