Preferences checkboxes have large invisible clickable areas

What is the issue?

Description

Checkboxes in the Transmission GTK Preferences window can be toggled by clicking empty space far to the right of the visible checkbox and its label.

For example, under Preferences → Network → Options, the Enable µTP for peer communication checkbox can be toggled by clicking apparently empty space hundreds of pixels to the right of its label.

This makes it possible to inadvertently change settings while clicking in otherwise empty areas of the Preferences window.

Steps to reproduce

1. Open Transmission GTK.
2. Open Preferences → Network.
3. Locate Enable µTP for peer communication.
4. Click empty space far to the right of the checkbox label on the same row.
5. Observe that the checkbox toggles.

GTK Inspector test

I investigated the affected checkbox using GTK Inspector.

The widget is:

gtkmm__GtkCheckButton — enable_utp_check

Its halign property is set to fill.

While halign=fill, clicking visually empty space hundreds of pixels to the right of the checkbox label toggles the checkbox.

I then changed halign from fill to start using GTK Inspector without restarting Transmission.

The distant empty space immediately stopped toggling the checkbox, while clicking the checkbox indicator or its label continued to work normally.

This suggests that the check button is horizontally expanding into the otherwise empty area of the Preferences window, making the entire expanded widget allocation clickable.

Expected behavior

The checkbox should be activated by clicking the checkbox itself or its associated label, not distant visually empty space in the Preferences window.

Possible fix

Setting the affected check buttons to halign=start, or otherwise preventing them from expanding across unused horizontal space, appears to eliminate the large invisible activation area.

System information

• Distribution: Arch Linux: kernel 7.2.4
• Session type: Wayland
• Compositor: Wayfire 0.12.0
• GTK version: 4.22.5
• Transmission GTK: 4.1.3
• GTK theme: Breeze-Dark
• GPU: NVIDIA GeForce GTX 1660 Ti
• NVIDIA driver: 615.71.09

transmission-gtk is linked against GTK 4:

libgtk-4.so.1 => /usr/lib/libgtk-4.so.1

Which application of Transmission?

GTK+ app on Linux, BSD, etc.

Which version of Transmission?

4.1.3