Crash upon resizing icons in theme colour

[Niet Beschikbaar]

OS version: Ubuntu 19.04
GIMP version: 2.10.8-2

Expected: icon size enlarges
What happened: crash of GIMP (image recoverable after re-opening GIMP)

Method to reproduce:
- Open Gimp
- Go to Preferences
- Choose icon theme "colour"
- try to enlarge the icon size

After re-opening Gimp and following the methods above, the crash does *not* occur.

[Niet Beschikbaar (lintfran)]

extra info generated by crash report:

```
GNU Image Manipulation Program version 2.10.8
git-describe: GIMP_2_10_6-294-ga967e8d2c2
C compiler:
 Using built-in specs.
 COLLECT_GCC=gcc
 COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/8/lto-wrapper
 OFFLOAD_TARGET_NAMES=nvptx-none
 OFFLOAD_TARGET_DEFAULT=1
 Target: x86_64-linux-gnu
 Configured with: ../src/configure -v --with-pkgversion='Ubuntu 8.2.0-13ubuntu1' --with-bugurl=file:///usr/share/doc/gcc-8/README.Bugs --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr --with-gcc-major-version-only --program-suffix=-8 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie --with-system-zlib --with-target-system-zlib --enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
 Thread model: posix
 gcc version 8.2.0 (Ubuntu 8.2.0-13ubuntu1)

using GEGL version 0.4.14 (compiled against version 0.4.12)
using GLib version 2.60.4 (compiled against version 2.58.1)
using GdkPixbuf version 2.38.1 (compiled against version 2.38.0)
using GTK+ version 2.24.32 (compiled against version 2.24.32)
using Pango version 1.42.3 (compiled against version 1.42.3)
using Fontconfig version 2.13.1 (compiled against version 2.13.0)
using Cairo version 1.16.0 (compiled against version 1.16.0)

```
> fatal error: Segmentatiefout

Stack trace:
```

# Stack traces obtained from PID 4099 - Thread 4099 #

[New LWP 4101]
[New LWP 4102]
[New LWP 4103]
[New LWP 4104]
[New LWP 4105]
[New LWP 4119]
[New LWP 4306]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
__libc_read (nbytes=256, buf=0x7ffe918d9190, fd=18) at ../sysdeps/unix/sysv/linux/read.c:26
  Id Target Id Frame
* 1 Thread 0x7fdfc0bcce00 (LWP 4099) "gimp-2.10" __libc_read (nbytes=256, buf=0x7ffe918d9190, fd=18) at ../sysdeps/unix/sysv/linux/read.c:26
  2 Thread 0x7fdfbfb4a700 (LWP 4101) "worker" syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
  3 Thread 0x7fdfbd75b700 (LWP 4102) "gmain" 0x00007fdfc28b6729 in __GI___poll (fds=0x56235fb29c40, nfds=2, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
  4 Thread 0x7fdfbc91c700 (LWP 4103) "gdbus" 0x00007fdfc28b6729 in __GI___poll (fds=0x56235fb3d0e0, nfds=3, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
  5 Thread 0x7fdfa65ad700 (LWP 4104) "async" syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
  6 Thread 0x7fdfa5dac700 (LWP 4105) "worker" syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
  7 Thread 0x7fdfa55ab700...

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.