The release notes of Tiger 5.15 says that "Double-clicking or tapping the image zooms into the clicked / tapped area". It actually works as advertised, but produces strange results when I double-click in a corner of an image, see the attached screenshots:

• The first one shows the result of the preview after a double-click in the place circled in red: the image is zoomed in, but shifted to the top right.
• The other screenshot shows the result after a 2nd double-click in the zoomed image (still in the red circle): the initial zoom level is restored, but the image is even more shifted

Is this a bug or a problem with my configuration or an incorrect setting?

Yes, the double-click targeting was not perfect in 5.15, I am aware. This was because the skin was written in the 2010s when IE compatibility was necessary, and IE could not handle CSS transformations the same way other browsers could. So some of the code has remained from the old times, and now I'm rewriting all the libraries to unify the old, mixed model to be based solely on "transform".

Yes, I'm working on the new version.