Check Box Tool
From GeoGebra Manual
Clicking in the 
Graphics View creates a check box (see section Boolean values) that allows you to show and hide one or more objects. In the appearing dialog window you can specify which objects should be affected by the check box.
Note: You may select these objects from the list provided in the dialog window or select them with the mouse in any view.
Comments
The check box itself is just the visual representation of a boolean variable, and the dialog is simply a convenient way of adding the boolean variable in the conditional visibility field of many objects at once. You could have done the same by selecting all the objects, then entered the name of the boolean value in the conditional visibility field manually to the selection.
