Can't create submenu in component by core function "JHtmlSidebar"

[Mausino]

Steps to reproduce the issue

I got message from my developer

" we are using the joomla core function "JHtmlSidebar" and for now it don't support the submenu layout"

Expected result

I can create submenus in by joomla function

Actual result

Can't use joomla framework for creating of submenu

System information (as much as possible)

Joomla 3.8.7
Php 7.2.5
MySQL 5.6

Additional comments

[tonypartridge]

JHTMLsidebar doesn’t have that facility and if you want it just add your own custom menu with sub menus?

Or your developer can do a pull request to the CORE to add such features

[joomla-cms-bot]

Set to "closed" on behalf of @franz-wohlkoenig by The JTracker Application at issues.joomla.org/joomla-cms/20532

[ghost]

Closed as above stated.

@Mausino if needed please ask help on the forums.