When I ask my webmail to print an email, the dialogue window pops us as expected. In that window I expect a small top bar with a close (cross) and print (printer) icons, as shown in the first image added (obtained with Linux Ubuntu 18.04, Firefox 71). Instead, in a computer with Linux Ubuntu 14.04 and Firefox 66, I get gigantic icons, as wide as the page width, as shown in the second image added. This is certainly an issue when I want to print to file; I have not tried and sent the job to a printer since I am not interested in that use at this moment. It used to work fine for years until a certain point, but I cannot pinpoint when it went wrong and the possible whys. Note that the body of the mail is formatted regularly, and that also the icons at the bottom (say, an attachment) are magnified disproportionately. There is an archived post in https://support.mozilla.org/en-US/questions/1176032 that reports a similar problem. However, the diagnose is different. The large icon is not an issue of yahoo mail on two counts: 1) the big X and printer icons are supposed to be there, and the issue is that they are magnified without a reason; 2) the problem does not arise with the same webmail service in other computers. I suspect that it must be some local setting of Firefox that has been changed in a mistake? Any ideas on fixes and workarounds? Thanks for helping out