Thunderbird - retrieves messages, it deletes them from my actual gmail inbox

I noticed that when Thunderbird retrieves messages, it deletes them from my actual gmail inbox.
Is there a way to have it retrieve messages without doing so, and have it delete the messages from my gmail inbox when I delete them manually in thunderbird?

The reason I'm using Thunderbird is because it's one click away to open my general use email and university email. But sometimes I may be away from my mac and might have to access my accounts elsewhere.

In the account settings preferences, go to server settings. There should be a checkbox labeled "Leave messages on server" under your Gmail account. If you wish to keep the messages on the server and therefore leave them online, ensure that this is checked. The setup instructions on the Gmail help page have you uncheck this box. Test it with a test email or two to ensure that everything is working the way you want it.

I'm sorry if I'm not that precise - I don't use TBird so I am trying to reverse the steps from the setup instructions.

Thanks for the reply

I asked on the Thunderbird forum and someone told me to set up my emails as IMAP accounts and tweak the settings a bit. Works like a charm