Overview line too narrow

Hi! I am using Cubase 10 and once in a while the Overview line of some project appears too narrow. Every time I open this particular project, the Overview line is small. I hardly can see it in te left corner. So I hhardly operate there in the Overview line. Yet on other projects it comes in normal size. What cuold the reason be and how could I make it normal size?
Thanks in advance! :slight_smile: