I’m using the postmessage command to reddot a user
Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As String) As Integer
The difference between PostMessage and SendMessage is that PostMessage just place the message in the windows thread queue and resturn immediately, and sendMessage blocks (the calling thread) untill the message has been processed.
If you intend to, or might, select another nick right after sending the message you need to use SendMessage to make sure it has been processed by paltalk, otherwise you can use PostMessage.