Remove the leftmost column from ranger file manager

There is a way I can remove the rightmost column:

# Preview files on the rightmost column?
# And collapse (shrink) the last column if there is nothing to preview?
set preview_files false
set preview_directories false
set collapse_preview true

But how do I remove the leftmost column which shows the parent directory? I know that I can use set viewmode=multipane to get single column. But in that case, when I use two tabs, I get two columns for two tabs, in the same screen. I want a screen per tab, but I want each screen to be composed of single column. How do I achieve that?