Confusion rule

Possibly confused words like from_form/know_now is not working in the current version (LT 4.2).
Is there any reason behind this??

Could you post example sentences? Have you set up everything according to Finding errors using Big Data - LanguageTool Wiki?

Thank you dnaber. Your reply helps me a lot.
Again a liitle doubt for me.
There is an option to control runonwords in spell suggestions. This is working perflectly if I merged two words by mistake. But what for prefixes and suffixes. Prefixes are split in suggestions. Not only prefixes and suffixes. Single letters are get split because of the runonwords suggestions. Please let me know a way to control these error captures and suggestions.
Example: This is prebook. There is no need to capture the word prebook.