Crash linking SVG element to feImage (1.1-dev)

Steps to reproduce:

• Open Inkscape
• Draw a rectangle
• Open the Filter Editor Dialog
• Add a filter
• Add the Image filter primitive to it
• Select the rectangle
• Press the "Selected SVG Element" button

What happened?

Crash (truncated backtrace attached, rest is signals from the mouse click)

Thread 1 "inkscape" received signal SIGSEGV, Segmentation fault.
SPDesktop::getSelection (this=0x0) at ../src/desktop.cpp:441
441		return selection;
(gdb) set pagination off
(gdb) bt
#0  0x00007f661e7e5cf6 in SPDesktop::getSelection() const (this=0x0) at ../src/desktop.cpp:441
#1  0x00007f661e4f14e1 in Inkscape::UI::Dialog::FileOrElementChooser::select_svg_element() (this=0x56126787b270) at ../src/ui/dialog/filter-effects-dialog.cpp:659
#2  0x00007f661e4f19c8 in sigc::bound_mem_functor0<void, Inkscape::UI::Dialog::FileOrElementChooser>::operator()() const (this=<optimised out>) at /usr/include/sigc++-2.0/sigc++/functors/mem_fun.h:1991

What should have happened?

No crash

Version Info:

• Inkscape 1.1-dev (57183a90, 2020-06-30, custom) Linux Mint 19.1
• Inkscape 1.1-dev (0c15f593, 2020-03-12) Linux Mint 19.1
• Bisection points

commit d977fb1001f310ede5d60239955a898e18c5650d
Author: Thomas Holder <thomas@thomas-holder.de>
Date:   Sun Jan 12 19:48:33 2020 +0100

    Hidden dialogs stop receiving desktop signals
    
    Use map/unmap signals to connect and disconnect the desktop.

Note that in 1.0.x it crashes if you then Ctrl+Q on the unsaved, still open file. The commit where this bug was introduced fixes that issue.