I don't know when this started, but noticed recently
I noticed that it no longer scales entirely to window size. and does appear to have a minimum size to display the last reply column. (985x1080)
For instance if I just have the window set to half my monitor size by using the shortcut of dragging it to the end of the monitor and letting windows resize to half ( monitor res: 1920 x 1080, half window is 960x1080)
If I drag the window a little bigger to 985x1080 then the last reply column appears.
would be nice if it scaled to window size.
Not sure if this is browser or website issue. I noticed it maybe a week or two ago and forgot to report it.