adds another submenu level (3rd level) to the categories menu module, the menu on the left...

you must have vqmod installed...

the extension works with the default theme and should work with other themes if the custom theme doesn't contain this file:

catalog/view/theme/???/template/module/category.tpl

'cause, if so, opencart gets this file from the default theme...

if the custom theme contains that file, you need to:

1. edit the .xml file and replace 'default' with 'your-theme-name'...

that's all...

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to replace, delete, change the arrow that points to the sub-submenu, edit the .xml file and replace:

↘

with > , - , or another char if you want it to show on ie9 and ie10 also, or another unicode arrow. you can find a list here:

http://character-code.com/arrows-html-codes.php

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this extension uses vqmod so it doesn't replace any file.
it should work with opencart 2.0.0.0 and newer, but it's only tested with OC 2.0.1.1. ++