Running Mint 19 and I have an issue that I have been unable to solve. I have multiple Slackware installs but my new mobo (Reizen) needed Linux Mint.

I have been running a program for years, par2, that when I double click on a par file in Krusader a terminal window would open and display the output of this program. The program runs in the background but all I see is the "spinny thing" until the program completes.

I have been unable to replicate this behavior in Mint. I see the same behavior in Krusader and in Thunar (the default file manager).

let me summarize:
this has been working on krusader and thunar, but not on Mint's default file manager?
if you're using cinnamon, that would be nemo, right?
how did you implement the double-click functionality?