Auto complete v. different to Intellij

Hi Forum

I'm a long time Intellij user, who is used to typing ..

_someClass.

at which point, I get the auto complete box. In Rider, (but not intellij)  I find that I have to wait for at least 1/2 second before pressing return, or to press cntrl space or select using the cursor, otherwise I get a carriage return. V. annoying! As I have to cursor back and start again.

Can anyone please, please tell me where to tweak this setting?