As @redallen explained:
Looks like this was a hack added in #1227 for inline editing. @suomiy said here:
inline edit needs input events. I can send back computedData which are a bit easier to consume and leave the decision logic on consumer. IMO this is the best what can be done. Does somebody have a better idea?
If inline-edit-extension works with changing the event we can convert it to onClick.
So, however the however the hack was introduced to make inline-edit-extension work i think it's erally obscure behavior for normal row clicks to react on mousedown.