./del key on numpad doesn't seem to work anywhere in Unity. I can alt tab to any other program and it works. Numlock on/off makes no difference. Not a big issue but just a pain when typing decimals in Inspector. 2018.2.2f1 on linux mint 19.
Bcoz Unity uses comma as a decimal separator. looks like it is broken in 2018.2.0 2018.2.4 not working as well.
Thanks, it looks like Gtk 3 handles these slightly differently than Gtk 2. A fix will be in an upcoming build.