Comment 1 for bug 57962

I can confirm this (up-to-date edgy) -- the missing pixel line is on the left (not on the right) here.

Not sure where this comes from. The icons themselves look fine, for example /usr/share/icons/hicolor/48x48/apps/deskbar-applet.png

A clue: maybe the default icon size for the dialog is not a standard one (it seems to take the 48 versions of icons, but they're definitely not displayed that big), and the resizing is not optimal?