I just purchased a HiDPI monitor and though I've been able to fix the bulk of problems following the Arch HiDPI guide, there are still many problems to fix and I can't identify some of the desktop elements so I can theme them properly.
I've been using the program GTKInspector to find css elements in various GTK apps so I can edit the theme, but I can't figure out how to do the same for for my xfce desktop. In GTKInspector you can drag a cross-hair (Widget Selector) over an element in a program and you can then see the GTK tree, along with the css elements so you can know what the element is called and hence you can override it in a custom gtk.css file.
I've tried launching xfce4-panel with debugging enabled, (Which is how you enable GTKInspector for a program) but it just won't work for xfce4-panel itself.
GTK_DEBUG=interactive xfce4-panel -r &
Is there a way to use GTKInspector on xfce4-panel, or another tool that would identify the existing theming elements? For example, I'd like to make the icons larger in the windows list.