If you would like to increase or decrease the size of the student screens, use the slider to the upper right of the student screens. If you move the slider to the left, the size of the screens decreases. Sliding this toggle all the way to the right shows only one student screen at a time.
If you want a quick full page view, click the full page icon next to the slider to open up the full page view. You can return to your class page by using the [x] in the upper right corner of the full page view.
The student is connected and broadcasting their screen. It's possible that the student is logged into Chrome in more than one location and Classroom is getting conflicting messages what to broadcast. The student can see if they're logged into multiple locations if they look in the Security tab under Manage my Google Account.
The connection to the student's device is in process. Usually you'll only see this for a short period while a connection is being established.
Usually the student is connected and the broadcast is happening, but the student may be viewing a page that will not broadcast such as an extension page. You can open the Student Information Panel and view the Tabs and History to usually see what the student is viewing, or trying to view.
This indicates that the student is offline.
The student is opening a new tab and has not yet searched for anything within that tab.