Update documentation.

doc/base/classes.xml

@@ -11281,7 +11281,7 @@
 			<argument index="1" name="title" type="String">
 			</argument>
 			<description>
-				Add a control to the bottom panel (together with Output, Debug, Animation, etc). If your plugin is being removed, also make sure to remove your control by calling [method remove_control_from_bottom_panel].
+				Add a control to the bottom panel (together with Output, Debug, Animation, etc). Returns a reference to the button added. It's up to you to hide/show the button when needed. If your plugin is being removed, also make sure to remove your control by calling [method remove_control_from_bottom_panel].
 			</description>
 		</method>
 		<method name="add_control_to_container">

tools/editor/editor_plugin.cpp

@@ -284,7 +284,7 @@ Control *EditorPlugin::get_base_control() {
 void EditorPlugin::_bind_methods() {
 
 	ObjectTypeDB::bind_method(_MD("add_control_to_container","container","control:Control"),&EditorPlugin::add_control_to_container);
-	ObjectTypeDB::bind_method(_MD("add_control_to_bottom_panel","control:Control","title"),&EditorPlugin::add_control_to_bottom_panel);
+	ObjectTypeDB::bind_method(_MD("add_control_to_bottom_panel:ToolButton","control:Control","title"),&EditorPlugin::add_control_to_bottom_panel);
 	ObjectTypeDB::bind_method(_MD("add_control_to_dock","slot","control:Control"),&EditorPlugin::add_control_to_dock);
 	ObjectTypeDB::bind_method(_MD("remove_control_from_docks","control:Control"),&EditorPlugin::remove_control_from_docks);
 	ObjectTypeDB::bind_method(_MD("remove_control_from_bottom_panel","control:Control"),&EditorPlugin::remove_control_from_bottom_panel);