Comment 10 for bug 1122853

Flock doesn't seem to be needed, this worked for me...

sed -i 's/\(--existing \)%U/\1-c '\''gui show'\''/' /usr/share/applications/hexchat.desktop

Essentially it just changes...

hexchat --existing %U

To...

hexchat --existing -c 'gui show'

The '--existing' part is meant to run a URL or a command in an existing copy of HexChat - so the %U is interpreted as a URL it doesn't comprehend so I think that makes the whole '--existing' argument invalid (so it opens a whole new copy, as though '--existing' wasn't specified). But putting '--existing -c' makes it run a command, that command being to bring the window to the foreground.