Firefox toolbar icon resizes on rollover
I have the latest version of Firefox, and am using the Zotero 4.0.28.10 plugin. I have the Zotero icons on the toolbar. Normally the 'Z' icon is separated from the 'page' icon by a vertical bar. When I mouse over the icons, the vertical bar disappears, which causes the entire toolbar to change spacing. Is this expected behavior?
However, on XUbuntu with Firefox 43 it looks for me wrong in the other direction, see https://gist.github.com/zuphilip/43659689290322adbc2e .