/editbox -n doesn't fill the editbox of the target if it is a hidden or minimized window.

//window -eh @name | editbox -n @name /help
/window -a @name

//window -en @name | editbox -n @name /help
/window -a @name

Both of these show a window with no editbox history.

However it does work if you combine the last command with the first two...
//window -eh @name | editbox -n @name /help | window -a @name
Code:
alias ebox.test {
  window -en @name
  editbox -n @name /timer
  .timer 1 1 echo -s - $!line(@name,0)
  .timer 1 2 window -c @name
}
Try it; /ebox.test

Now try it with activating the window; //ebox.test | window -a @name