Also my English may not make that much sense because it is from the Google translation
This is the extension
Your help will be invaluable because that way I can understand more about how this programming works:grinning:
So far my planning is this
You are mis-using the First Removed event.
You should not use it to remove another item from the Firebase list.
Also, global chatlist can not possibly be a tag.
Read the tool tip for that event block.
@Android_Creator only extension authors are allowed to publish extensions...
therefore I removed the extension and replaced it by a link to the extension...
Taifun
Trying to push the limits! Snippets, Tutorials and Extensions from Pura Vida Apps by 
Taifun.
Regarding "How to make cloudDB chat with private rooms "
How to create separate chat rooms might help you figure your code out.
This is a sample app and is made be adding some very simple modifications to the original App Inventor ChatApp. You can probably improve the UI or maybe add a login system...
Chatting.aia (9.6 KB)
Thank you all for your help☺
The file because it is in aia format does not allow me to put it as an extension
Because it's an app project, not an extension.
What do you mean?
Go to Projects >> Import AIA and select the downloaded .AIA file.