Resizing columns in My Files online

I am trying to resize the Name / Modified / Modified By etc. columns when looking at my documents in My Files online. However, the cursor automatically switches to selection rather than resizing the columns. When I hover the mouse between the columns, the cursor changes to the two headed arrow you expect to see. However, when I click it changes to selection instead. It is very frustrating as it makes reading the file names extremely difficult. I can't seem to find a fix to this issue. Thanks in advance if anyone knows how to.