Here are two specific issues, with screenshots comparing the "small" (relatively speaking) window views with larger window views:
On the main help screen, some of the text bubbles for the toolbar interfere with the Quick Help Topics entries, obscuring vision and interrupting clickability.
Upon selecting an entry, the "BACK" button is similarly obscured and interrupted by the text bubbles.
Here are two specific issues, with screenshots comparing the "small" (relatively speaking) window views with larger window views: