QtCreator - how to control font size on Help file opened in Edit mode?

Hello,

In QtCreator, under Tools->Options->Help, the Font Size seems like has no control on the font size in the Help file launched by the F1 click in editor? In my case, that font is too big, but I cannot find a way to adjust it. Note that the mode is Edit mode.

The font size set under Tools->Options->Help only controls the font in Help mode, i.e., file launched by the click on Help on the left window or the Help menu.

Has anyone seen the same problem? Can you point out how to adjust the font size of Help file while in Edit mode? Thank you.