Hi @ed.chan thanks for posting in the community - I'm happy to help! The option for line jumps can be found in the Line settings section of Page Settings. To turn this on/off navigate to File > Page Settings > Line Connections and toggle the option for "Show Line Jumps". 

I've included a screenshot showing where you can find this option:

You can also enable/disable this through the Line style box in the formatting bar. 

For more information I recommend taking a look at the Work with Lines article and Page and Document settings article from the Help Center. 

Feel free to let me know if you have any questions. Hope this helps! 

FYI Line Jumps are now under:
File > Document Settings

...within the Document Settings dialog, click “Lines” on the left -- and then you’ll see on the right the option for “Show line jumps”

Thanks for sharing the updated location, @philCryo! We have made some updates since my previous response above, and Page Settings is now Documents Settings.

You can still adjust this for individual lines through the Line style box in the formatting bar. Hope this helps! :)