STR:

1. Start with MOZ_ENABLE_WAYLAND=1 on Ubuntu 22.04.
2. Create a bookmark toolbar folder with a long list of items.
3. Unmaximize the window and move it down the screen so that the bookmark toolbar folder popup appears above the window.
4. Drag and drop bookmark items around in the popup.

The drop indicator cannot be moved beyond the limits of the window but the actual drag and drop operation works at the location of the cursor regardless. When dragging too far away from the window, the drop indicator and drop location becomes offset from the cursor.

Looks like a problem with the indicator itself. Drop is performed correctly (with Bug 1794597 fixed).

On Wayland drop target position can be a negative value. Drop target area can contain empty elements located at 0,0 with zero size.
If we hit such combination the drop element is placed at 0,0 and we don't consider other valid elements located at negative positions.
That leads to incorrect drop target indicatop placement; it's located at 0,0 coordinates.

In this patch we ignore empty elements and iterate through valid ones only so we correctly place drop indicator even when screen coordinates are negative.

https://hg.mozilla.org/mozilla-central/rev/d18532398463

The patch landed in nightly and beta is affected.
:stransky, is this bug important enough to require an uplift?

• If yes, please nominate the patch for beta approval.
• If no, please set status-firefox107 to wontfix.

For more information, please visit auto_nag documentation.

No need to backport, rather minor bug which was here since beginning.

Reproducible on a 2022-09-20 Nightly build(wayland session) on Ubuntu 22. Verified as fixed on Firefox 108.0b2(build ID: 20221115200658, wayland session) and Nightly 109.0a1(build ID: 20221116182402, wayland session) on Ubuntu 22.