Manipulation API UI doesn't appear when using vis-network in angular 8+

[Lakhder Amine]

I'm using vis-network in an angular 8+ based application, and when i'm trying to use the manipulation api to edit nodes/edges, the UI doesn't appear, it seems like the css of the vis-network is not loaded, i tried to do it manually (add vis-network css files), but always something missing from the orginal UI (no colors, no font-size style like the original one), anyone have an idea about this, is it a bug, or just the integration with angular doesn't fit. Thanks in advance.