Culling layout (dynamic mode) does not utilize available screen space

Is there an existing issue for this?

• I checked and did not find my issue in the already reported ones

Describe the bug

Hi there,

I have recently started using Darktable and have noticed that the culling mode (dynamic) uses a layout that seems less than ideal.
To be specific, one image is fine as it will fill the empty space when zooming in:

Two images make sense as well as all the space is used:

Three images is where the issue starts, as there is empty space and even zooming in will not cause the images to take up that space:

Four images (the maximum that still allows for zooming) is using even less space, and zooming keeps the initial sizing as well:

This is on a 21:9 screen and running the latest version from AUR 5.5.0+904

Thank you very much for your time.

Steps to reproduce

1. Go to lighttable
2. Enter culling mode (dynamic)
3. Select three or four images
4. Zoom in

Expected behavior

The images grow to make full use of the available space (like they do when viewing only one or two images)

Where did you obtain darktable from?

self compiled

darktable version

5.5.0+904~g8d95339436

What OS are you using?

Linux

What is the version of your OS?

CachyOS (up to date as of 2026-04-06) running KDE Plasma with Wayland

Are you using OpenCL GPU in darktable?

Yes

If yes, what is the GPU card and driver?

AMD 9070XT and mesa (version 26.0.4-2 from cachyos)

Start in the lighttable's culling mode (dynamic) and reproduce the layout with three and four selected images, then compare it with one and two images while zooming. Trace the code responsible for sizing and arranging culling images. Done means three- and four-image layouts expand to use the available screen space when zoomed, without regressing the one- and two-image layouts.