Broken zooming and scrolling in the map view on Ubuntu 26.04

Is there an existing issue for this?

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

Describe the bug

After updating my Ubuntu from 25.10 to 26.04 and updating darktable from v5.4.0 to v5.4.1, zooming in the map view via touch pad scrolling is no longer possible. I can only use the OSD to zoom in and out ("+" and "-" buttons). It is also no longer possible to change the size of locations on the map by scrolling.

Steps to reproduce

Zooming:

1. Go to the map view
2. Move the mouse pointer to the map widget
3. Scroll up/down

Change size of map locations:

1. Go to the map view
2. Create a new (ellipse shaped) map location
3. Move the mouse pointer to the map widget inside the created map location
4. Scroll up/down

Expected behavior

The map should be zoomed in/out and the size of the created map location should increase/decrease.

Logfile | Screenshot | Screencast

No response

Commit

No response

Where did you obtain darktable from?

distro packaging

darktable version

5.4.1

What OS are you using?

Linux

What is the version of your OS?

Ubuntu 26.04

Describe your system

No response

Are you using OpenCL GPU in darktable?

None

If yes, what is the GPU card and driver?

No response

Please provide additional context if applicable. You can attach files too, but might need to rename to .txt or .zip

At first, I checked if this is an issue with darktable 5.4.1, but it isn't. I installed darktable 5.4.0, which didn't show this problem before on Ubuntu 25.10, but on Ubuntu 26.04 zooming and scrolling is broken with darktable 5.4.0 as well.

Second, I compiled and installed an instrumented darktable 5.4.1 to generate debug output at the entry point of different callback functions handling GTK events of the map widget. This revealed that the callback function _view_map_scroll_event() related to the GTK signal "scroll-event" is never triggered, whereas other callback functions are triggered as expected.

This seems to be a GTK issue with the map widget related to the "scroll-event".

Start in src/views/map.c, especially the map widget's GTK event connections and _view_map_scroll_event(). Reproduce the missing scroll-event behavior on Ubuntu 26.04 and compare it with the working callbacks described in the issue. Done means map scrolling zooms the view and changes map-location sizes again.