pcbnew: Ratsnest lines dissapear after routing

[Michael Geselbracht]

If there are two or more pads belonging to the same net and no tracks are connecting these pads, ratsnest lines are displayed in order to indicate the connection.

Now, if there are more than two pads of the same net and two pads are connected with the routing tool all remaining ratsnest lines for this net disappear. The lines re-appear when the 'B' is pressed.

Steps to reproduce:
1. Open the pic_programmer demo.
2. Move cursor over the 'VCC' track connecting 'U3' and 'C1' and press 'I' followed by 'DEL'.
   --> no ratsnest lines appear
3. Press 'B' --> ratsnest lines appear for net 'VCC'
4. Route a track from 'U3' pad 3 to 'C1' pad 1. --> Remaining ratsnest lines disappear.

git bisect came up with commit 4c37defd3 for this issue.

Application: kicad
Version: (5.0.1-dev-152-gf591f8741), debug build
Libraries:
    wxWidgets 3.0.4
    libcurl/7.58.0 OpenSSL/1.1.0g zlib/1.2.11 libidn2/2.0.4 libpsl/0.19.1 (+libidn2/2.0.4) nghttp2/1.30.0 librtmp/2.3
Platform: Linux 4.15.0-34-generic x86_64, 64 bit, Little endian, wxGTK
Build Info:
    wxWidgets: 3.0.4 (wchar_t,wx containers,compatible with 2.8) GTK+ 2.24
    Boost: 1.65.1
    OpenCASCADE Community Edition: 6.9.1
    Curl: 7.58.0
    Compiler: GCC 7.3.0 with C++ ABI 1011

Build settings:
    USE_WX_GRAPHICS_CONTEXT=OFF
    USE_WX_OVERLAY=OFF
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_WXPYTHON=OFF
    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 89a3d2b45156d350d25f2a5b8909cc36a719c8c0
https://git.launchpad.net/kicad/patch/?id=89a3d2b45156d350d25f2a5b8909cc36a719c8c0