Layout preference Pane 3 problem with selecting Packet Diagram or None

Summary

Pane 3 takes over the complete panes area when selecting Packet Diagram or None.

Sample capture file

Any capture file will do.

Steps to reproduce

1. Open capture file
2. Open preferences
3. Select Layout and click restore defaults (just to start from a defined point)
4. For Pane 3 select the Packet Diagram radio button
5. Click Apply and observe the Pane 1 and Pane 2 disappear, and Pane 3 maintain Packet Bytes layout
6. For Pane 3 select the Packet Bytes radio button
7. Click Apply and see normal layout restored

What is the current bug behavior?

Given: 1) a loaded capture file, 2) the default layout for panes.
When selecting for Pane 3 either Packet Diagram or None and click Apply, the pane content stays Packet Bytes and takes over the whole application window area allocated for the three panes. The other two are no longer visible.
When selecting for Pane 3 Packet Bytes again the layout returns to normal.

This bug is seen on HEAD of branches release-4.6 and master, but not release-4.4
This could not be reproduced with the 4.6.0 release package on MacOS.

What is the expected correct behavior?

The layout should stay intact and the selected pane 3 should be shown.

Build information

Version 4.6.1 (v4.6.1rc0-44-g4636bdbc7eea).

Compile-time info:
 Bit width: 64-bit
  Compiler: GCC 15.2.0
      GLib: 2.86.0
 With:
  +brotli                      +nghttp2 1.64.0
  +Gcrypt 1.11.2               +nghttp3 1.12.0
  +GnuTLS 3.8.10 and PKCS#11   +PCRE2 10.46 2025-08-27
  +Kerberos (MIT)              +POSIX capabilities (Linux)
  +libnl 3                     +Qt 6.9.2
  +libpcap                     +QtDBus
  +libsmi 0.5.0                +QtMultimedia
  +libxml2 2.14.6              +Snappy 1.2.2
  +Lua 5.4.8                   +xxhash 0.8.3
  +LZ4 1.10.0                  +zlib 1.3.1
  +MaxMind                     +Zstandard 1.5.7
 Without:
  -automatic updates  -Minizip            -zlib-ng

Runtime info:
      OS: Linux 6.12.31-amd64
     CPU: Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz (with SSE4.2)
  Memory: 15689 MB of physical memory
    GLib: 2.86.0
  Locale: LC_TYPE=en_US.UTF-8
 Plugins: supported, 21 loaded
 With:
  +brotli 1.1.0                      +nghttp3 1.12.0
  +c-ares 1.34.5                     +PCRE2 10.46 2025-08-27
  +Gcrypt 1.11.2                     +QPA plugin "xcb"
  +GnuTLS 3.8.10                     +Qt 6.9.2
  +libpcap 1.10.5 (with TPACKET_V3)  +Xorg
  +libsmi 0.5.0                      +xxhash 803
  +light display mode                +zlib 1.3.1
  +LZ4 1.10.0                        +Zstandard 1.5.7
  +nghttp2 1.64.0
 Without:
  -HiDPI