To reproduce, "direct connect" to a server and paste in an IP or address (or anything really). Notice that the "Join Server" button does not become enabled as it should, and the user has to add/delete text to enable it.

Additionally, this specific text box exhibits two other unusual properties:
1. It appears selected when opening the menu, but actually is not.
2. If there is already text inside (from previously editing it), the button will be enabled even after all the text is removed.