Created attachment 5223 add wmdock.desktop.in.in to POTFILES.in wmdock.desktop.in.in contains translatable strings, so it should be added to POTFILES.in, attached patch does this.
Hi Yves, patch applied in commit b40cdeadda078a462c5a25df29222e14ab6c095b on git.xfce.org. Thank you for reporting Cheers Andre