Excel 2019 Chart Time Format
 

In previous versions of Excel, my X axis which is elapsed time, could be
custom formatted by entering the min, max etc. in the direct time format of
00:00:00 (hh:mm:ss). I am now using Excel 2010. If I want to enter, for
example, the major division value of 1 hour, I can no longer enter 01:00:00.
I must calculate the decimal equivalent of 1/24 and enter that number. What
am I missing?