This bug also occurs in Safari Version 18.3 (19620.2.4.111.8, 19620) so is probably WebKit's bug.
I have a system with two displays; the right-hand display is set as the primary display. This means (0, 0) is on that display, and causes the left-hand display to have negative x-coordinates. When I tried it, the coordinates of the Orion window were (-1763, 572).
When Orion (or Safari) is on the left hand display, interacting with the input at https://harrisonbroadbent.com/blog/cool-native-html-elements/#:~:text=Searchable%20dropdowns%20with%20datalist the popover containing the datalist's values appears nowhere near the input, or the browser window, but appears near the bottom left of the screen.
It behaves as expected when the window is on the right-hand display and thus has a non-negative x-coordinate.
Reproduction steps:
- Have two displays
- Arrange the displays in Settings > Displays > Arrange… so that they are in the right order, and drag the menu bar in that window to the right-hand display
- Visit the link above in Orion
- When Orion is on the left-hand display, the popover will appear in the wrong place; when it is on the right-hand display, it will appear in the right place.
The popover appears directly under the input.
0.99.131.0.2-beta (WebKit 621.1.2.111.4) macOS 14.7.4 (23H420)
Sonoma (14)