Consider the following sequence:
1) launch a Modelica tool and open an empty model
2) drag in a Modelica.Blocks.Interfaces.RealInput
3) drag in a Modelica.Blocks.Continuous.Integrator.
4) Do not resize anything.
The result is very different in Dymola and OpenModelica.
In OpenModelica the interface will have the same size of the integrator and text on the interface is very tiny.
Opposite to this in Dymola the interface will have a larger size than the integrator and text on the interface is roughly the same size of the integrator's.
Is there a mistake in one of the tools or there is a flaw in the MSL code of these two simple models?

It seems to me that the latter is true, since the text height on RealInput is 25 while the one on Integrator is 40.
But management of size elements in Modelica is so complex that I cannot judge well (cfr Otter's explanation on #1635 of Modelica issue tracking).