lightbeam24
Modern YouTube sidebar appears on old layout when using lower resolution screen
My secondary monitor is an old one: It has an aspect ratio of 4:3 and a resolution of 1024x768. When I load custom tube on it, the modern YouTube sidebar (the one that appears on lower resolution displays) appears. Of course, this isn't really an issue on the more modern layouts; but if I select an older one where this sidebar wouldn't be present, it's kind of a stain on the layout and even obstructs a few elements in some cases.
I know this is going to sound weird, but try enabling "Always show sidebar", and tell me if that fixes things.
That option forces the regular sidebar to always be visible no matter which page you're on, and no matter your zoom level. I believe it also hides the mini sidebar (the one in your screenshot). It was intended for the modern layouts, but I guess it works on the older layouts too, since the older layouts force hide the sidebar on pages such as the watch page. Perhaps I should bake the functionality into all layouts from 2012 and earlier.