exact_highlight_select uses mouse event's coordinates instead of highlight's coordinates
I haven't noticed this until now because I usually use single_click_selects_words 1. Sometimes this fails, e.g. in equations or occasionally at the end of sentences, and I switch to character selection mode using double click. When adding a highlight the entire word is selected. This also happens when using single clicks and single_click_selects_words 0.
There is anexact_highlight_select config option to configure this behavior.
Thanks, I hadn't seen that one when looking at the code. That option does not work well when selecting entire words though, as it seems to use the mouse coordinates. I'll fix this sometime this weekend.