I was having this issue since September and it still happens almost every time I try to use TP. Somewhere I found a temporary solution – try to open “Options” window with TP window still open, and change your game language – for example English → French, wait for TP to reload, and back to your original language. This method works for me almost every time, so I don’t have to restart GW2.
However, it will be veeery nice to see this bug fixed one day…