Marketo recently started showing their sidebar in the opposite direction, as if they were supporting Hebrew. It is however, annoying, as they base their UI direction not on the language choice of the user preference, but on the browser navigation language that will usually be set as Hebrew for Israeli users.
This means we get the sidebar on the Right side, even though our language is set to English in Marketo's UI.
Quick Solution? Change the browser language.
In (up-to-date) Chrome, browser language can be set by the going to the following URL: chrome://settings/languages
Make sure to set English as the FIRST language in the list - Restart chrome afterwards.
If all is well, your navigation language will be set to 'en' or 'en-US'. You can check it via Chrome dev tools here, by typing in the console: window.navigator.language
voilà - Marketo looks sane(r) again: