There is a KB describes how to fix right click issue in IE on vSphere Web Client. But my problem was in Chrome. I searched a lot in internet but no lucky till today.

The problem was flash menu appears when I right click anything in vSphere Web Client in Chrome. I have two computers that both has Chrome installed but one has issue, other one works fine. I compared version of Chrome, noticed working one was 55.x, problematic one was 49.x. The issue gone after upgraded to 57.x.

After dig into that problem, looks like Google fixed the problem on version 54.0.2840 that there was a bug related to right click. Check out release notes here.