Set a variable and check it before sending the text.
Code:
alias check {
  if ($len($editbox($active)) >= 1) {
    if (%Typing != $true) {
      echo -ag Typing-Message $true
    }
    set -u15 %Typing $true
  }
  else {
    if (%Typing) {
      echo -ag Typing-Message: $false
      unset %Typing
    }
  }
}


This will only display $true once and only $false once. As a note, the way you had the $true part, if you typed 2 letters before it checked, it wouldn't display $true because it wouldn't be == 1.

Note: Although it shouldn't be needed, I put -u15 to unset the %Typing variable just to prevent possible problems. It should unset automatically anyhow, but I like being thorough. smile