What steps will reproduce the problem? 1. Use the Wireless monitor with <quality> in its template and set -p 3. 2. Move near and far from a wireless network you are connected to in order to make it switch back and forth from 100% to anything lower.

What is the expected output? What do you see instead? I expect to see "100" and then " 97" or whatever the signal quality is (importantly, with the space in front of it), but the space is not there.

What version of the product are you using? On what operating system? xmobar 0.13 Arch Linux

In xmobar 0.13, quality isn't treated as a percentage, and, therefore, -p has no effect. I'm fixing that in the repo (and in 0.14). In the meantime, you can use -m 3 to (more or less) the same effect.