Perspective session show icons randomly

In a Perspective project on Ignition 8.0.7, there are icons that I can see on the Designer, but most of the times are they are not visible in the open session (tested from web browser - Chrome, Firefox - and iPad - iOS), despite they do not have any binding for the “Visible” property. There is even an example (please see images below) in which two sessions were open at the same time from the same browser, and one of them shows the icons and the other does not.

Is this a bug?