The Panel selector (2) indicates the panel name and allows to change the contents of it.
Clicking on the panel designation to the left in the panel selector opens a drop-down menu in which you can change the content of this panel at any time without having to close the panel and open another (exceptions are ETS Apps that were explicitly created to behave this way).
You can mark a panel as favorite so that it is always shown in the panel selector by going to 'All panels' and then by clicking the 'Star' icon of the respective panel. Clicking the 'Star' icon again removes the panel from the favorites and hides it from the panel selector.
App panels can be also added as favorites in the panel selector in the same way.
The action '' opens the currently selected panel in a new tab.
The action '' opens the currently selected panel in a new ETS window.
The action '' moves the currently selected panel one position higher and the action '' moves the currently selected panel one position lower (in case there are 2 or more panels open).
In case of vertical presentation of the panels, those actions become 'Move left' and 'Move right' to move the panels left, respectively right.
The action '' closes the currently selected panel. A panel may also be closed by hovering the panel selector and clicking the middle button of the mouse (or the mouse wheel).
Because the content of each panel can be set individually, this feature can be used to display two or more panels of the same type. This can be useful e.g. for comparing the parameter settings of two devices.