gebrview crashes when opening an empty file

This is the contents of my B_SilkS which causes crash

```
G04 #@! TF.GenerationSoftware,KiCad,Pcbnew,(5.99.0-158-g78859b29e)*
G04 #@! TF.CreationDate,2019-10-01T13:01:51-04:00*
G04 #@! TF.ProjectId,lightning-protection-pcb-panel,6c696768-746e-4696-9e67-2d70726f7465,rev?*
G04 #@! TF.SameCoordinates,Original*
G04 #@! TF.FileFunction,Legend,Bot*
G04 #@! TF.FilePolarity,Positive*
%FSLAX46Y46*%
G04 Gerber Fmt 4.6, Leading zero omitted, Abs format (unit mm)*
G04 Created by KiCad (PCBNEW (5.99.0-158-g78859b29e)) date 2019-10-01 13:01:51*
%MOMM*%
%LPD*%
G04 APERTURE LIST*
G04 APERTURE END LIST*
M02*
```

This is the NPTH.drl that causes crash/hang

```
M48
; DRILL file {KiCad (5.99.0-158-g78859b29e)} date Tuesday, October 01, 2019 at 01:01:57 PM
; FORMAT={-:-/ absolute / inch / decimal}
; #@! TF.CreationDate,2019-10-01T13:01:57-04:00
; #@! TF.GenerationSoftware,Kicad,Pcbnew,(5.99.0-158-g78859b29e)
; #@! TF.FileFunction,NonPlated,1,2,NPTH
FMAT,2
INCH
%
G90
G05
T0
M30
```

I cannot reproduce the crash

@ocb-hd-ccb Can you attach the crash report from Console.app?

This is an example file. I cannot open this with gerbview...

I don't have a crash report show up in console.app it just is unresponsive. I don't actually know very much about console.app but when I enter 'gerbview' into the search window nothing is populated.

```
Application: KiCad
Version: (5.99.0-279-gaf837ed76), debug build
Libraries:
    wxWidgets 3.0.4
    libcurl/7.64.1 SecureTransport (LibreSSL/2.8.3) zlib/1.2.11 nghttp2/1.39.2
Platform: Mac OS X (Darwin 19.0.0 x86_64), 64 bit, Little endian, wxMac
Build Info:
    Build date: Oct 29 2019 15:23:31
    wxWidgets: 3.0.4 (wchar_t,STL containers,compatible with 2.8)
    Boost: 1.69.0
    OpenCASCADE Community Edition: 6.9.1
    Curl: 7.54.0
    Compiler: Clang 9.0.0 with C++ ABI 1002

Build settings:
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_PYTHON3=OFF
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_WXPYTHON_PHOENIX=OFF
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=ON
    KICAD_USE_OCC=OFF
    KICAD_SPICE=ON
    KICAD_STDLIB_DEBUG=OFF
    KICAD_STDLIB_LIGHT_DEBUG=OFF
    KICAD_SANITIZE=OFF
```

Can't get this to crash in linux.

When you say unresponsive, do the menus work? Do you get a spinning beach ball? Can you quit the application without force quitting?

If you have to force quit, can you click "Report" and then copy/paste the report text information to this bug report?

Application: GerbView
Version: (5.99.0-283-g65bf66938-dirty), debug build
Libraries:
    wxWidgets 3.0.4
    libcurl/7.64.0 OpenSSL/1.1.1d zlib/1.2.11 libidn2/2.0.5 libpsl/0.20.2 (+libidn2/2.0.5) libssh2/1.8.0 nghttp2/1.36.0 librtmp/2.3
Platform: Linux 4.19.0-6-amd64 x86_64, 64 bit, Little endian, wxGTK
Build Info:
    Build date: Oct 30 2019 09:22:28
    wxWidgets: 3.0.4 (wchar_t,wx containers,compatible with 2.8) GTK+ 3.24
    Boost: 1.67.0
    OpenCASCADE Community Edition: 6.9.1
    Curl: 7.64.0
    Compiler: GCC 8.3.0 with C++ ABI 1013

Build settings:
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_PYTHON3=ON
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_WXPYTHON_PHOENIX=ON
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=ON
    KICAD_USE_OCC=OFF
    KICAD_SPICE=ON
    KICAD_STDLIB_DEBUG=OFF
    KICAD_STDLIB_LIGHT_DEBUG=OFF
    KICAD_SANITIZE=OFF

Yes, it is just a beach ball. It is completely unresponsive. No menus no nothing.

I have to force quit but there isn't a 'report' button after I force quit. Is there somewhere else?

That's odd.

Can you follow this procedure to sample the process and copy the data returned?

https://support.apple.com/guide/activity-monitor/run-system-diagnostics-actmntr2225/mac

Hope this helps.

So, I may have additional information about this...

It doesn't appear to crash/freeze on open of the file. It is when I move the window after opening. I have a large monitor and when I open it is pretty small in the upper left corner. It appears to open and not hang until I move that window and/or attempt to resize the window.

Doing the same action with a gbr that isn't blank works perfectly.

I can't reproduce this with the file from #4 (or any other Gerber).

Same OS, same wxWidgets. Build flags slightly different, but I don't think there's any scripting hookup for GerbView, and OCE isn't involved is it?

Application: GerbView
Version: (5.99.0-345-g55432d968-dirty), debug build
Libraries:
    wxWidgets 3.0.4
    libcurl/7.57.0 OpenSSL/1.0.2n zlib/1.2.11 libidn2/2.0.4 libpsl/0.19.1 (+libidn2/2.0.4)
Platform: Mac OS X (Darwin 18.7.0 x86_64), 64 bit, Little endian, wxMac
Build Info:
    Build date: Nov 7 2019 21:20:53
    wxWidgets: 3.0.4 (wchar_t,STL containers,compatible with 2.8)
    Boost: 1.66.0
    Curl: 7.57.0
    Compiler: Clang 11.0.0 with C++ ABI 1002

Build settings:
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=OFF
    KICAD_SCRIPTING_PYTHON3=OFF
    KICAD_SCRIPTING_WXPYTHON=OFF
    KICAD_SCRIPTING_WXPYTHON_PHOENIX=OFF
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=OFF
    KICAD_USE_OCC=OFF
    KICAD_SPICE=ON
    KICAD_STDLIB_DEBUG=OFF
    KICAD_STDLIB_LIGHT_DEBUG=OFF
    KICAD_SANITIZE=OFF

KiCad bug tracker has moved to Gitlab. This report is now available here: https://gitlab.com/kicad/code/kicad/-/issues/2564