Thanks for the crash log. I've reproduced a crash that matches it by selecting a code-formatted property name in the help window and then resizing the window. The text renderer mishandles the existing selection when the layout changes. A multi-monitor setup isn't needed to trigger it.
I've logged the bug, and I will fix the selection handling so resizing or maximising the help window preserves the selection without crashing.
For now, you can use Open Online in the help window to read the documentation in your browser.