Bug 292058 – [GTK] Incorrect and offset custom drag-and-drop previews on Trello.com and similar implementations

• Component: WebKitGTK
• Status: NEW

[Jeff Fortin]

Created attachment 475044 [details]
Demonstration video on Trello.com

With Epiphany 48 (WebKitGTK 2.48.1), Technology Preview, etc., as well as any previous version, drag-and-drop is broken compared to other browsers (ex: Firefox) on websites that use custom previews for drag operations, such as Trello.

Please see the two attached videos comparing Epiphany incorrect rendering (and offset position from the mouse cursor) with Firefox's correct rendering and behavior. One video is recorded on a Trello.com kanban board, while the other is on an independent imitation I found on https://www.codemzy.com/blog/trello-drag-and-drop-in-react

[Jeff Fortin]

Created attachment 475045 [details]
Demonstration video on an independent imitation of Trello's drag-and-drop behavior

[Jeff Fortin]

The ReactJS code snippet implementation linked above at least lets you test something similar without needing to login to Trello as a first step; it's not *exactly* the same symptoms on the Epiphany side (as you can see it also gets "stuck" in the 2nd video, unlike in the 1st video), but it's pretty close.