Moving dockable dialogs crashes Inkscape

Summary:

There's an exceptionally high chance that moving a dockable dialog can just crash Inkscape.

Steps to reproduce:

1. Open Inkscape
2. Locate a docked dialog in the right-side panel
3. Attempt to either undock it or change where it is docked with the mouse.

What happened?

A few different things have happened in my testing:

• A duplicate of the dragged dialog opens in the middle of the screen. Letting go of the primary mouse button crashes Inkscape.
• The dialog successfully undocks from the right-side panel. Dragging it now crashes Inkscape.
• The dialog successfully undocks from the right-side panel. Dragging it now crashes Inkscape and creates a duplicate of the dialog over the crash handler.
• Inkscape just gives up, taking the crash handler with it.

Video examples

First_Dialog_Move_Works__Second_Move_Crashes.mkv

Duplicate_Dialog_Crash.mkv

Duplicate_Dialog_Crash_after_First_Dialog_Move_Works.mkv

Duplicate_Dialog_over_Crash_Handler.mkv

What should have happened?

Ideally, this shouldn't crash. It doesn't crash every single time, but in my testing so far, being able to exit without a crash has happened only once.

Version info

<pre>
 0# Inkscape::Application::crash_handler(int) in /app/bin/../lib/inkscape/libinkscape_base.so.1.4.2.0
 1# 0x00007F90768425C0 in /usr/lib/x86_64-linux-gnu/libc.so.6
 2# 0x00007F9074B27EB4 in /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
 3# 0x00007F9074C9ADE3 in /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
 4# g_cclosure_marshal_VOID__OBJECTv in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 5# 0x00007F9076508B52 in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 6# 0x00007F90765200C0 in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 7# g_signal_emit_by_name in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 8# 0x00007F9074E12035 in /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
 9# 0x00007F9076508B52 in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
10# 0x00007F90765200C0 in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
11# g_signal_emit_by_name in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
12# 0x00007F90750A314D in /usr/lib/x86_64-linux-gnu/libgdk-3.so.0
13# 0x00007F9073D0C056 in /usr/lib/x86_64-linux-gnu/libffi.so.8
14# 0x00007F9073D0ADB1 in /usr/lib/x86_64-linux-gnu/libffi.so.8
15# ffi_call in /usr/lib/x86_64-linux-gnu/libffi.so.8
16# 0x00007F907359D0EE in /usr/lib/x86_64-linux-gnu/libwayland-client.so.0
17# 0x00007F907359D959 in /usr/lib/x86_64-linux-gnu/libwayland-client.so.0
18# wl_display_dispatch_queue_pending in /usr/lib/x86_64-linux-gnu/libwayland-client.so.0
19# 0x00007F907509A550 in /usr/lib/x86_64-linux-gnu/libgdk-3.so.0
20# gdk_display_get_event in /usr/lib/x86_64-linux-gnu/libgdk-3.so.0
21# 0x00007F907509A21E in /usr/lib/x86_64-linux-gnu/libgdk-3.so.0
22# 0x00007F9077104BFA in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
23# 0x00007F9077106F17 in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
24# g_main_context_iteration in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
25# g_application_run in /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
26# main in inkscape
27# 0x00007F907682B3C8 in /usr/lib/x86_64-linux-gnu/libc.so.6
28# __libc_start_main in /usr/lib/x86_64-linux-gnu/libc.so.6
29# _start in inkscape
</pre>
<details><summary>System info</summary>
Inkscape 1.4.2 (ebf0e940d0, 2025-05-08)

                      Compile  (Run)
    GLib version:     2.84.1
    GTK version:      3.24.49 (3.24.49)
    glibmm version:   2.66.1
    gtkmm version:    3.24.5
    libxml2 version:  2.13.6
    libxslt version:  1.1.42
    Cairo version:    1.18.4 (1.18.4)
    Pango version:    1.56.3 (1.56.3)
    HarfBuzz version: 9.0.0 (9.0.0)

    OS version:       GNOME 48 (Flatpak runtime)
</details>

Line 4# would sometimes be 4# g_closure_invoke in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0 in the crash log instead; they were otherwise identical.