Blank/broken 'close' icon on multi-window hover
After compiling and installing the plugin as described in the Gitlab instructions, I noticed that the close/X icon is showing what appears to be a default placeholder icon.
This happens with both the Adwaita and GNOME icon themes on Fedora 34; I noticed that switching to the "Mint-X, Mint-Y" themes resolves this, so it appears to work under some themes, but not most of the common/default themes I have installed.