Macro doesnt work inside textbox

[onsight]

I use this macro to change specific text, but it doesnt work, when text is inside text boxes. If text is in table cell, then macro work fine. What I must change in code, that will affect text in text boxes too, not just in table cell?
This is code:

Sub Podpisi()
With ActiveDocument.Content.Find
 .Execute FindText:="blue", ReplaceWith:="Mr." & vbCr & "Adrian Tomc", _
 Format:=True, Replace:=wdReplaceAll
End With
End Sub