Monospace Font - Not Really Monospace?

This appears to be a bug that I've found using JavaScript in Gedit (when you change the font from 'Ubuntu mono' to 'Monospace') and Geany so far. I have a right margin set to 80 ch

Solution 1:

It's probably because your default monospace font doesn't have a native bold style. Just change the font. I'd suggest since you're in Linux, DejaVu Sans Mono or Liberation Mono; they'll work just fine.

Also, you'd think monospace would have a native bold style by now

If you're in Ubuntu you can download Unsettings and change the default monospace font so when you open programs that have "monospace" as font it'll be the one you chose.

Btw, this is not unique to Linux. Check out the default monospace font on a Windows cmd...

Solution 2:

In my case changing font didn't help. The solution was to select option Insert spaces instead of tabs in the Preferences/Editor.