This is documentation for Mathematica 8, which was
based on an earlier version of the Wolfram Language.
View current documentation (Version 11.1)

Opener

Opener[x]
represents an opener with setting x, displayed as when x is True and when x is False.
Opener[Dynamic[x]]
takes the setting to be the dynamically updated current value of x, with the value of x being toggled if the opener is clicked.
Dynamically change a variable:
Dynamically change a variable:
In[1]:=
Click for copyable input
Out[1]=
Change the appearance:
By default the opener changes only when you click it:
By setting AutoAction, the opener toggles as the mouse moves over the opener area:
Change the background color:
Align with surrounding text:
By default Opener is enabled:
By setting Enabled->False, the opener is disabled but visible in its current state:
Include margins around the Opener:
Use Opener with PaneSelector for hiding and exposing additional controls:
Opener is a special case of Toggler:
OpenerView is a combination of Opener and PaneSelector:
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