Uh oh! What happened here?
In this case, the reason the row indicator letters can’t be read is that the font size is too big. To change any of those characteristics, go to Tools | Seating plans | <Highlight the seating plan> that you want to modify and click on the settings tab. See screen shot below:
Initially, the Chart font size was set to 16. Once we change it to 8, look what happens. The row indicator numbers are readable. This flexibility lets you customize how your chart looks.