How to clean a textarea?

In the old version there was no problem with:

SetGadgetText(textarea,"")

But in the new it doesn't work?????
And because of this i tryed:

Local zeilen = TextAreaLen(code_input, 2)

For i = 0 To zeilen
zeichen = TextAreaLineLen(code_input, i)
SetTextAreaText(code_input, "", i, zeichen, 1)
Next

For z.inhalt = Each inhalt
AddTextAreaText code_input, z\code$ + Chr$(13)+Chr$(10)
Next

But its also not working?

Do you have any advicements?

Both SetGadgetText and SetTextAreaText work fine here. Check your code.