Ribbon size

Hello PPlanners,

I know my question will look strange to most of you;

is there a way in MSP 2016 to fix or freeze the height of the ribbon? 

What I mean is: in MSP the ribbon normally is of the same height as in MX Excel or Word, somewhere under 2 inches on my screen; and, all of a sudden, the height increases dramatically, to more than 2 inches

if I collapse the ribbon, and display the ribbon by selecting one tab or the other, the ribbon displays at its normal height.

I cannot say where this behaviour comes from; maybe something in the registry?

Thank you for your help,

Alexandre