the activate editor for the plugin didn't appear

I installed “live composer” and I activate it from plugins and it did’t appear the buttom “Activate editor” I tried other themes like the twenty fifteen and other themes and nothing worked. I removed all the plugins that may make conflict and also it didn’t work
I think its some thing in the setting and I can’t figure out

please help and thanks in advance

https://www.ads-software.com/plugins/live-composer-page-builder/