Created attachment 2242 Patch for main.c as described I had a need for bits of coloured text in the XFCE panel. xfce-genmon-plugin was exactly what I wanted except for the inability to set colours. This patch allows use of the gtk pango markup in the text passed to xfce-genmon-plugin and thus one can colour the text. The patch simply changes a couple of calls from gtk_label_set_text() to gtk_label_set_markup(), I have also increased the text buffer size because the markup can use quite a bit of 'non-displayed' space. The patch is applied to main.c in xfce4-genmon-plugin-3.2/panel-plugin. I have added the patch as an attachment - cgpatch.
*** Bug 5751 has been marked as a duplicate of this bug. ***
Patch applied. Thanks for submitting it.