I’m sure this can be solved by Insync’s devs, but how much effort will this require is another question. Is this a Qt5 bug? Should Insync implement the SNI protocol and communicate via DBus? Some apps do this (e.g. iwgtk).
I suggest that you solve this locally.
Option 1: Edit the desktop file.
1.a. Copy the
1.b Open the copied desktop file in a text editor, and change the value of the
Exec key to
env XDG_CURRENT_DESKTOP=Unity insync start.
Or just run
desktop-file-edit --set-key=Exec --set-value='env XDG_CURRENT_DESKTOP=Unity insync start' ~/.local/share/applications/insync.desktop.
Option 2: Auto-start
Check if you have
/usr/bin/xembedsniproxy and then set your desktop to auto-start it.
If you can’t find it, then try locating it
In Arch Linux, this is already set to auto-start by shipping
/etc/xdg/autostart/xembedsniproxy.desktop, so I believe that unless the user overrode it, then it should already be running. I’m not running Plasma on my daily driver, so I might be wrong here.