Using latest WebCore (2.4.5.3) in Delphi 12:
When setting the .font.size property of a TWebStringGrid at design time, the grid shows up with this font size.
But changes of the font size at runtime have no effect...
I thought that it might be because my grid sits an a modal form.
But a quick test with a small test app shows that .invalidate really doesn't help with updating the grid regarding the font.size.
Switching the .visible property helps, and then .invalidate is not necessary.