When I had Slackware on my testing partition, I installed i3 after installing Openbox and LXAppearance. i3 displayed icons and window themes normally, but after installing Slackware on my main partition, I decided to go with i3, instead of Openbox. I have a small problem. i3 does not display icons in the file manager (Thunar) and in other applications, like Firefox, displays some kind of dull default icons. I can open Qt and Xfce settings managers, so I tried using the Xfce settings. Those settings had no effect, so today I tried Qt's settings, hoping not to cause a settings conflict and mess things up. Again no effect.

i3's documentation is void of such issues and so far the only thing useful I have found elsewhere is editing ~/gtk.rc, which is not applicable in this case. I do not understand how installing LXAppearance and Openbox (and obconf) last time could be related, because they do not have any dependencies. And this installation of Slackware is the same as my previous test installation, except for LibreOffice not yet being installed.

Is it a case of i3 working with obconf and/or LXApearance, but not with other settings managers? I do not want to install packages from SlackBuilds on a trial-and-error basis, hoping to stumble upon the right package, especially since that is unlikely to be the problem. I am hoping it is a simple matter of editing a configuration file, but the only such settings in ~/i3/config are for window border colours.

I am at a bit of a loss and hope I have not somehow messed up something.

I went ahead and experimented with trial-and-error. Luckily the first stab in the dark worked. Installing LXAppearance allows i3 to display icons and change founts. I have no idea why my i3 needs LXAppearance, but as long as it is working.