Same result here. The issue is the equals sign, removing it makes the game show up and lets me add it. According to the spec for .desktop files (http://standards.freedesktop.org/desktop-entry-spec/latest/ar01s03.html) the equals sign is allowed as a part of the "value" in a key=value pair. I don't have your parsing code handy; if I did I'd also offer a patch to fix those.
WINEPREFIX="/home/thoemy/.wine"x1 2013-02
The first problems seems to be that Steam does not find the following .desktop file in
~/.local/share/applications/wine/Programme/Grinding Gear Games/Path of Exile.desktop.But copying it directly to
~/.local/share/applications/still doesn't list it. Removing theenv WINEPREFIX="/home/thoemy/.wine"part from the Exec line lets it appear in the list but it doesn't start with the following output.The
env WINEPREFIX="/home/thoemy/.wine"is not needed on the command line.Also directly adding this .desktop file with the browse button has no effect.