[Plugin: WordPress Page Tree] Widget not available for more than one use

I like this plugin alot. I am using it on several sites.
I am also using Custom sidebars and I need to place the PageTree widget on several different custom sidebars with different settings.

I have drug and dropped the widget into my first sidebar and it is working fine. Problem is, the Pagetree widget now no longer appears under my Available Widgets. As if I am only allowed to use it once in one place.

Can anyone tell me how to fix this?

https://www.ads-software.com/extend/plugins/page-tree/