Parameter syntax:

[ 
  ('showLevel' '1'|'2'|'3'|'4'|'5'|'6'|'7'|'8'|'9') |
  'state'|'toggle'|'collapse'|'expand'|'collapseAll'|'expandAll'
]?

The "showLevel N" option allows to expand all the collapsible views of the document up to nesting level N and to recursively collapse all the collapsible views having a nesting level greater than N. For example, invoking "toggleCollapsed showLevel 1" or "toggleCollapsed showLevel 2" just after opening a large DocBook document may be used to display the outline of this document (that is, the list of its collapsed parts or chapters).

All the other options: state, toggle, collapse, etc, change the state of the nearest collapsible view.

The “nearest collapsible view” is searched like this:

If this collapsible view is not found, then this command cannot be executed.

If this collapsible view is found, then this command returns a string, "expanded" or "collapsed", which reflects the state of the collapsible view after applying the operations specified in its parameter.

The default operation is toggle. Supported operations are:

Sample bindings (as found in the add-on called "A sample customize.xxe" — download and install it using Options → Install Add-ons):

<binding>
  <keyPressed code="ESCAPE" />
  <charTyped char="1" />
  <command name="toggleCollapsed" parameter="showLevel 1" />
</binding>

<binding>
  <keyPressed code="ESCAPE" />
  <charTyped char="/" />
  <command name="toggleCollapsed" />
</binding>

<binding>
  <keyPressed code="ESCAPE" />
  <charTyped char="+" />
  <command name="toggleCollapsed" parameter="expandAll" />
</binding>

<binding>
  <keyPressed code="ESCAPE" />
  <charTyped char="-" />
  <command name="toggleCollapsed" parameter="collapseAll" />
</binding>