Info button not seen for some users

[RV8]

Hello All,

My team has developed a QlikSense app in which we added a info button on every chart like here - 

. The idea is to display KPI definitions upon hovering the button. the issue we are facing is , it is not visible to some of them including me. One of users who did not experience this issue in the beginning is now facing it. We tried  checking in multiple browsers  and update the browsers as well but in vain.  Can some one help me understand the reason for this behavior and possible solution