I can’t figure out how to navigate to the Print an envelope dialog in Writer?
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Unfortunately not, I’m running Libreoffice 5.4.6.2 on Kubuntu 17.10 and after clicking the properties button I find the selection drop down is greyed out and set to A4 despite having set C5 on the format tab and the dimensions there being correct and as soon as it is inserted the dimensions change to 250 x 176