pcbnew: preview items masked by selection

[Seth Hillbrand]

When an item is selected, any items displayed in the preview layer (ruler, cursor info, etc) are not visible.

You can observe this by selecting a zone and then attempting to measure it.

Application: kicad
Version: (6.0.0-rc1-dev-396-ge160eb067), release build
Libraries:
    wxWidgets 3.0.2
    libcurl/7.52.1 OpenSSL/1.0.2l zlib/1.2.8 libidn2/0.16 libpsl/0.17.0 (+libidn2/0.16) libssh2/1.7.0 nghttp2/1.18.1 librtmp/2.3
Platform: Linux 4.9.0-7-amd64 x86_64, 64 bit, Little endian, wxGTK
Build Info:
    wxWidgets: 3.0.2 (wchar_t,wx containers,compatible with 2.8) GTK+ 2.24
    Boost: 1.62.0
    OpenCASCADE Community Edition: 6.8.0
    Curl: 7.52.1
    Compiler: GCC 6.3.0 with C++ ABI 1010

Build settings:
    USE_WX_GRAPHICS_CONTEXT=OFF
    USE_WX_OVERLAY=OFF
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=ON
    KICAD_USE_OCC=OFF
    KICAD_SPICE=OFF

[KiCad Janitor (kicad-janitor)]

Fixed in revision 20ea48637845ed3cb71f95b657e49d2bf88d756f
https://git.launchpad.net/kicad/patch/?id=20ea48637845ed3cb71f95b657e49d2bf88d756f