Comment 2 for bug 1830633

Hello, there still a point that needs to be fixed (it is still possible to loose data in this way):

If you creatc the second child sheet with copy/paste before the first sheet has been saved you get a
"Error occurred opening schematic file..."
"Unable to open filename "....

then clicking OK you can place the "empty copy"
If you save now you get the old behaviour loosing data from the first and second child sheet.

workaround: save the schematic before pasting the file.

To reproduce the bug:
Create a new child sheet, DON't SAVE now.
put something on it, Don't save.
go up one level and create a new child sheet copying the old one, now:
-you get an error (the child sheet file is not found since it has not been saved)
-click OK
Place the new sheet. Since the file has not been loaded it is empty.
Save now and you loose the content of the child sheet (old and new).

Tested on revision cb83f8acdfdfc1f7659e7e87d2e0696520150bc9.

----------------------------------------------------------------------------
Application: Eeschema
Version: (5.1.0-843-gcb83f8acd), release build
Libraries:
    wxWidgets 3.0.2
    libcurl/7.52.1 OpenSSL/1.0.2r 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 4.9.0-8-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_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