Doing alt-F to get to the Filter field (as indicated on UI) locates you to Print Size's Width. Doing Alt-T also sets you to Print Size's Width as intended.
Thanks for the report, I can confirm the issue.
Git commit 061b838ab6154ba9cf7642be29fed0de5637a31e by Boudewijn Rempt. Committed on 01/09/2018 at 13:03. Pushed by rempt into branch 'rempt/T379-resource-management'. Fix broken buddy M +10 -10 plugins/extensions/imagesize/wdg_imagesize.ui https://commits.kde.org/krita/061b838ab6154ba9cf7642be29fed0de5637a31e
Git commit c1ffff954c8c7b114c900dc40d957e0275b85b3f by Boudewijn Rempt. Committed on 03/09/2018 at 07:17. Pushed by rempt into branch 'master'. Fix broken buddy M +10 -10 plugins/extensions/imagesize/wdg_imagesize.ui https://commits.kde.org/krita/c1ffff954c8c7b114c900dc40d957e0275b85b3f
Git commit 0be98df8250b76a8af3c2e2c1d1cfb825f0d92b4 by Boudewijn Rempt. Committed on 07/09/2018 at 12:52. Pushed by rempt into branch 'krita/4.1'. Fix broken buddy M +10 -10 plugins/extensions/imagesize/wdg_imagesize.ui https://commits.kde.org/krita/0be98df8250b76a8af3c2e2c1d1cfb825f0d92b4